diff --git a/src/fhirtypes/ElementDefinition.ts b/src/fhirtypes/ElementDefinition.ts
index 6b8b2b8fd..c585fdc35 100644
--- a/src/fhirtypes/ElementDefinition.ts
+++ b/src/fhirtypes/ElementDefinition.ts
@@ -11,7 +11,7 @@ import {
 } from 'lodash';
 import { minify } from 'html-minifier-terser';
 import { isUri } from 'valid-url';
-import { StructureDefinition } from './StructureDefinition';
+import { PathPart, StructureDefinition } from './StructureDefinition';
 import {
   CodeableConcept,
   CodeableReference,
@@ -66,7 +66,8 @@ import {
   setPropertyOnDefinitionInstance,
   splitOnPathPeriods,
   isReferenceType,
-  isModifierExtension
+  isModifierExtension,
+  getArrayIndex
 } from './common';
 import {
   Fishable,
@@ -284,6 +285,7 @@ export class ElementDefinition {
   structDef: StructureDefinition;
   private _original: ElementDefinition;
   private _edStructureDefinition: StructureDefinition;
+  private _replacementProps: string[][];
 
   /**
    * Constructs a new ElementDefinition with the given ID.
@@ -291,6 +293,7 @@ export class ElementDefinition {
    */
   constructor(id = '') {
     this.id = id;
+    this._replacementProps = cloneDeep(REPLACEMENT_PROPS);
   }
 
   get id(): string {
@@ -472,6 +475,54 @@ export class ElementDefinition {
     this._original = undefined;
   }
 
+  clearOriginalProperty(pathParts: PathPart[]): void {
+    let currentOriginalElement: any = this._original;
+    // eslint-disable-next-line
+    let currentActualElement: any = this;
+    const clearPath = this.calculateClearPath(pathParts);
+    for (const [i, pathPart] of clearPath.entries()) {
+      if (i < clearPath.length - 1) {
+        const key = pathPart.primitive ? `_${pathPart.base}` : pathPart.base;
+        currentOriginalElement = currentOriginalElement?.[key];
+        currentActualElement = currentActualElement?.[key];
+        const currentIndex = getArrayIndex(pathPart);
+        if (currentIndex != null) {
+          if (Array.isArray(currentOriginalElement)) {
+            currentOriginalElement = currentOriginalElement[currentIndex];
+          }
+          if (Array.isArray(currentActualElement)) {
+            currentActualElement = currentActualElement[currentIndex];
+          }
+        }
+      } else {
+        if (currentOriginalElement?.[pathPart.base] != null) {
+          currentOriginalElement[pathPart.base] = undefined;
+          currentActualElement[pathPart.base] = undefined;
+        }
+        if (pathPart.primitive && currentOriginalElement?.[`_${pathPart.base}`] != null) {
+          currentOriginalElement[`_${pathPart.base}`] = undefined;
+          currentActualElement[`_${pathPart.base}`] = undefined;
+        }
+      }
+    }
+  }
+
+  private calculateClearPath(pathParts: PathPart[]): PathPart[] {
+    const replacementIndex = this._replacementProps.findIndex(
+      replacementPath =>
+        replacementPath.length <= pathParts.length &&
+        replacementPath.every((rp, index) => rp === pathParts[index].base)
+    );
+    if (replacementIndex >= 0) {
+      // Build the clearPath from the actual pathParts, since we want to know about primitive types.
+      const clearPath = pathParts.slice(0, this._replacementProps[replacementIndex].length);
+      // each replacement property only has to get cleared once, so remove it from the list.
+      this._replacementProps.splice(replacementIndex, 1);
+      return clearPath;
+    }
+    return [];
+  }
+
   /**
    * Determines if the state of the current element differs from the stored "original".
    * @returns {boolean} true if the state of the current element differs from the stored "original", false otherwise
@@ -3136,3 +3187,13 @@ const PROPS_AND_UNDERPROPS: string[] = PROPS.reduce((collect: string[], prop) =>
  * See http://hl7.org/fhir/elementdefinition.html#interpretation.
  */
 const ADDITIVE_PROPS = ['mapping', 'constraint'];
+
+/**
+ * These list properties are replaced in child profiles. If they are modified
+ * in a profile, the snapshot should contain only entries in that profile,
+ * and not in the parent profile. Each property is given as a list of
+ * path parts.
+ * For more context and a specific example, see this Zulip thread:
+ * https://chat.fhir.org/#narrow/stream/215610-shorthand/topic/restricting.20aggregation.20type/near/413120070
+ */
+const REPLACEMENT_PROPS = [['type', 'aggregation']];
diff --git a/src/fhirtypes/common.ts b/src/fhirtypes/common.ts
index f2638f995..c7b73fcc6 100644
--- a/src/fhirtypes/common.ts
+++ b/src/fhirtypes/common.ts
@@ -91,6 +91,9 @@ export function setPropertyOnDefinitionInstance(
 ): void {
   const instanceSD = instance.getOwnStructureDefinition(fisher);
   const { assignedValue, pathParts } = instanceSD.validateValueAtPath(path, value, fisher);
+  if (instance instanceof ElementDefinition) {
+    instance.clearOriginalProperty(pathParts);
+  }
   if (!(instance instanceof CodeSystem || instance instanceof ValueSet)) {
     const knownSlices = determineKnownSlices(instanceSD, new Map([[path, { pathParts }]]), fisher);
     setImpliedPropertiesOnInstance(instance, instanceSD, [path], [], fisher, knownSlices);
diff --git a/test/export/StructureDefinitionExporter.test.ts b/test/export/StructureDefinitionExporter.test.ts
index 78edecc27..a511b7127 100644
--- a/test/export/StructureDefinitionExporter.test.ts
+++ b/test/export/StructureDefinitionExporter.test.ts
@@ -8189,6 +8189,229 @@ describe('StructureDefinitionExporter R4', () => {
       expect(ed.type[0]).toEqual(expectedType);
       expect(loggerSpy.getAllMessages()).toHaveLength(0);
     });
+
+    it('should apply CaretValueRules on the aggregation of a type and replace the parent values', () => {
+      // Profile: ParentObservation
+      // Parent: Observation
+      // * component ^type.aggregation[0] = #contained
+      // * component ^type.aggregation[1] = #referenced
+      const parentObservation = new Profile('ParentObservation');
+      parentObservation.parent = 'Observation';
+      const parentAggregationContained = new CaretValueRule('component');
+      parentAggregationContained.caretPath = 'type.aggregation[0]';
+      parentAggregationContained.value = new FshCode('contained');
+      const parentAggregationReferenced = new CaretValueRule('component');
+      parentAggregationReferenced.caretPath = 'type.aggregation[1]';
+      parentAggregationReferenced.value = new FshCode('referenced');
+      parentObservation.rules.push(parentAggregationContained, parentAggregationReferenced);
+      doc.profiles.set(parentObservation.name, parentObservation);
+      // Profile: ChildObservation
+      // Parent: ParentObservation
+      // * component ^type.aggregation[0] = #contained
+      const childObservation = new Profile('ChildObservation');
+      childObservation.parent = 'ParentObservation';
+      const childAggregationContained = new CaretValueRule('component');
+      childAggregationContained.caretPath = 'type.aggregation[0]';
+      childAggregationContained.value = new FshCode('contained');
+      childObservation.rules.push(childAggregationContained);
+      doc.profiles.set(childObservation.name, childObservation);
+
+      exporter.export();
+      const parentSd = pkg.profiles[0];
+      const parentComponent = parentSd.elements.find(el => el.id === 'Observation.component');
+      expect(parentComponent.type[0].aggregation).toEqual(['contained', 'referenced']);
+      const childSd = pkg.profiles[1];
+      const childComponent = childSd.elements.find(el => el.id === 'Observation.component');
+      expect(childComponent.type[0].aggregation).toEqual(['contained']);
+      expect(childComponent.calculateDiff().type[0].aggregation).toEqual(['contained']);
+    });
+
+    it('should apply CaretValueRules on elements within the aggregation of a type and replace the parent values', () => {
+      // Profile: ParentObservation
+      // Parent: Observation
+      // * component ^type.aggregation[0] = #contained
+      // * component ^type.aggregation[1] = #referenced
+      // * component ^type.aggregation[1].extension[0].url = "http://example.org"
+      // * component ^type.aggregation[1].extension[0].valueString = "parent value"
+      const parentObservation = new Profile('ParentObservation');
+      parentObservation.parent = 'Observation';
+      const parentAggregationContained = new CaretValueRule('component');
+      parentAggregationContained.caretPath = 'type.aggregation[0]';
+      parentAggregationContained.value = new FshCode('contained');
+      const parentAggregationReferenced = new CaretValueRule('component');
+      parentAggregationReferenced.caretPath = 'type.aggregation[1]';
+      parentAggregationReferenced.value = new FshCode('referenced');
+      const parentExtensionUrl = new CaretValueRule('component');
+      parentExtensionUrl.caretPath = 'type.aggregation[1].extension[0].url';
+      parentExtensionUrl.value = 'http://example.org';
+      const parentExtensionValue = new CaretValueRule('component');
+      parentExtensionValue.caretPath = 'type.aggregation[1].extension[0].valueString';
+      parentExtensionValue.value = 'parent value';
+      parentObservation.rules.push(
+        parentAggregationContained,
+        parentAggregationReferenced,
+        parentExtensionUrl,
+        parentExtensionValue
+      );
+      doc.profiles.set(parentObservation.name, parentObservation);
+      // Profile: ChildObservation
+      // Parent: ParentObservation
+      // * component ^type.aggregation[0].extension[0].url = "http://example.org"
+      // * component ^type.aggregation[0].extension[0].valueString = "child value"
+      // * component ^type.aggregation[0] = #contained
+      // * component ^type.aggregation[1] = #bundled
+      const childObservation = new Profile('ChildObservation');
+      childObservation.parent = 'ParentObservation';
+      const childExtensionUrl = new CaretValueRule('component');
+      childExtensionUrl.caretPath = 'type.aggregation[0].extension[0].url';
+      childExtensionUrl.value = 'http://example.org';
+      const childExtensionValue = new CaretValueRule('component');
+      childExtensionValue.caretPath = 'type.aggregation[0].extension[0].valueString';
+      childExtensionValue.value = 'child value';
+      const childAggregationContained = new CaretValueRule('component');
+      childAggregationContained.caretPath = 'type.aggregation[0]';
+      childAggregationContained.value = new FshCode('contained');
+      const childAggregationBundled = new CaretValueRule('component');
+      childAggregationBundled.caretPath = 'type.aggregation[1]';
+      childAggregationBundled.value = new FshCode('bundled');
+      childObservation.rules.push(
+        childExtensionUrl,
+        childExtensionValue,
+        childAggregationContained,
+        childAggregationBundled
+      );
+      doc.profiles.set(childObservation.name, childObservation);
+
+      exporter.export();
+      const parentSd = pkg.profiles[0];
+      const parentComponent = parentSd.elements.find(el => el.id === 'Observation.component');
+      expect(parentComponent.type[0].aggregation).toEqual(['contained', 'referenced']);
+      expect(parentComponent.type[0]._aggregation).toEqual([
+        null,
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'parent value'
+            }
+          ]
+        }
+      ]);
+      const childSd = pkg.profiles[1];
+      const childComponent = childSd.elements.find(el => el.id === 'Observation.component');
+      expect(childComponent.type[0].aggregation).toEqual(['contained', 'bundled']);
+      expect(childComponent.type[0]._aggregation).toEqual([
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'child value'
+            }
+          ]
+        },
+        null
+      ]);
+      const childComponentDiff = childComponent.calculateDiff();
+      expect(childComponentDiff.type[0].aggregation).toEqual(['contained', 'bundled']);
+      expect(childComponentDiff.type[0]._aggregation).toEqual([
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'child value'
+            }
+          ]
+        },
+        null
+      ]);
+    });
+
+    it('should apply CaretValueRules on elements within the aggregation of a type and replace the children of parent values when there is no parent value', () => {
+      // Profile: ParentObservation
+      // Parent: Observation
+      // * component ^type.aggregation[1].extension[0].url = "http://example.org"
+      // * component ^type.aggregation[1].extension[0].valueString = "parent value"
+      const parentObservation = new Profile('ParentObservation');
+      parentObservation.parent = 'Observation';
+      const parentExtensionUrl = new CaretValueRule('component');
+      parentExtensionUrl.caretPath = 'type.aggregation[1].extension[0].url';
+      parentExtensionUrl.value = 'http://example.org';
+      const parentExtensionValue = new CaretValueRule('component');
+      parentExtensionValue.caretPath = 'type.aggregation[1].extension[0].valueString';
+      parentExtensionValue.value = 'parent value';
+      parentObservation.rules.push(parentExtensionUrl, parentExtensionValue);
+      doc.profiles.set(parentObservation.name, parentObservation);
+      // Profile: ChildObservation
+      // Parent: ParentObservation
+      // * component ^type.aggregation[0].extension[0].url = "http://example.org"
+      // * component ^type.aggregation[0].extension[0].valueString = "child value"
+      // * component ^type.aggregation[0] = #contained
+      // * component ^type.aggregation[1] = #bundled
+      const childObservation = new Profile('ChildObservation');
+      childObservation.parent = 'ParentObservation';
+      const childExtensionUrl = new CaretValueRule('component');
+      childExtensionUrl.caretPath = 'type.aggregation[0].extension[0].url';
+      childExtensionUrl.value = 'http://example.org';
+      const childExtensionValue = new CaretValueRule('component');
+      childExtensionValue.caretPath = 'type.aggregation[0].extension[0].valueString';
+      childExtensionValue.value = 'child value';
+      const childAggregationContained = new CaretValueRule('component');
+      childAggregationContained.caretPath = 'type.aggregation[0]';
+      childAggregationContained.value = new FshCode('contained');
+      const childAggregationBundled = new CaretValueRule('component');
+      childAggregationBundled.caretPath = 'type.aggregation[1]';
+      childAggregationBundled.value = new FshCode('bundled');
+      childObservation.rules.push(
+        childExtensionUrl,
+        childExtensionValue,
+        childAggregationContained,
+        childAggregationBundled
+      );
+      doc.profiles.set(childObservation.name, childObservation);
+
+      exporter.export();
+      const parentSd = pkg.profiles[0];
+      const parentComponent = parentSd.elements.find(el => el.id === 'Observation.component');
+      expect(parentComponent.type[0].aggregation).toBeUndefined();
+      expect(parentComponent.type[0]._aggregation).toEqual([
+        null,
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'parent value'
+            }
+          ]
+        }
+      ]);
+      const childSd = pkg.profiles[1];
+      const childComponent = childSd.elements.find(el => el.id === 'Observation.component');
+      expect(childComponent.type[0].aggregation).toEqual(['contained', 'bundled']);
+      expect(childComponent.type[0]._aggregation).toEqual([
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'child value'
+            }
+          ]
+        },
+        null
+      ]);
+      const childComponentDiff = childComponent.calculateDiff();
+      expect(childComponentDiff.type[0].aggregation).toEqual(['contained', 'bundled']);
+      expect(childComponentDiff.type[0]._aggregation).toEqual([
+        {
+          extension: [
+            {
+              url: 'http://example.org',
+              valueString: 'child value'
+            }
+          ]
+        },
+        null
+      ]);
+    });
   });
 
   describe('#ObeysRule', () => {