diff --git a/app/graphql/mutations/postpone_grading_lock.rb b/app/graphql/mutations/postpone_grading_lock.rb
new file mode 100644
index 000000000..cb7965b65
--- /dev/null
+++ b/app/graphql/mutations/postpone_grading_lock.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+module Mutations
+  class PostponeGradingLock < BaseMutation
+    argument :registration_id, ID, required: true, loads: Types::RegistrationType
+    argument :qnum, Integer, required: true
+    argument :pnum, Integer, required: true
+    argument :notes, String, required: true
+
+    field :released, Boolean, null: false
+    field :grading_lock, Types::GradingLockType, null: false
+
+    def authorized(registration:, **_args)
+      return true if registration.course.all_staff.exists? context[:current_user].id
+
+      raise GraphQL::ExecutionError, 'You do not have permission.'
+    end
+
+    def resolve(registration:, qnum:, pnum:, notes:)
+      GradingLock.transaction do
+        ev = registration.exam_version
+        question = ev.db_questions.find_by(index: qnum)
+        part = question.parts.find_by(index: pnum)
+        lock = registration.grading_locks.find_by(registration: registration, question: question, part: part)
+        raise GraphQL::ExecutionError, 'That part is not being graded.' unless lock
+
+        raise GraphQL::ExecutionError, 'Must leave a non-empty note when postponing grading.' if notes.blank?
+
+        check_permissions_for_lock(context[:current_user], lock)
+
+        updated = lock.update(notes: notes)
+        raise GraphQL::ExecutionError, lock.errors.full_messages.to_sentence unless updated
+      
+        HourglassSchema.subscriptions.trigger(
+          :grading_lock_updated,
+          { exam_id: HourglassSchema.id_from_object(ev.exam, Types::ExamType, nil) },
+          lock,
+        )
+        { released: false, grading_lock: lock }
+      end
+    end
+
+    private
+    
+    def check_permissions_for_lock(user, lock)
+      owns_lock = lock.grader == user
+      return if owns_lock
+
+      raise GraphQL::ExecutionError, 'You do not have permission.'
+    end
+  end
+end
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