diff --git a/controllers/v2/unavailability/api.py b/controllers/v2/unavailability/api.py
index e876e6d9..ef01ed6b 100644
--- a/controllers/v2/unavailability/api.py
+++ b/controllers/v2/unavailability/api.py
@@ -1,11 +1,12 @@
 from flask_restful import reqparse, Resource, marshal_with, inputs
 
 from .response_models import volunteer_unavailability_time
-from domain import UserType
+from domain import UserType, session_scope
 from repository.volunteer_unavailability_v2 import EventRepository
 from services.jwk import requires_auth, is_user_or_has_role
 from controllers.v2.v2_blueprint import v2_api
-
+import logging
+from exception import EventNotFoundError, InvalidArgumentError
 edit_parser = reqparse.RequestParser()
 edit_parser.add_argument("title", type=str)
 edit_parser.add_argument("start", type=inputs.datetime_from_iso8601)
@@ -22,14 +23,21 @@ def __init__(self, event_repository: EventRepository = EventRepository()):
     @requires_auth
     @is_user_or_has_role(None, UserType.ROOT_ADMIN)
     def put(self, user_id, event_id):
-        args = edit_parser.parse_args()
-        success = self.event_repository.edit_event(user_id, event_id, **args)
-        if success is True:
+        try:
+            with session_scope() as session:
+                args = edit_parser.parse_args()
+                self.event_repository.edit_event(session, user_id, event_id, **args)
             return {"message": "Updated successfully"}, 200
-        elif success is False:
-            return {"message": "Event not found"}, 404
-        else:
-            return {"message": "Unexpected Error Occurred"}, 400
+        except InvalidArgumentError as argumentException:
+            logging.warning(argumentException)
+            return {"message": "Invalid argument from the payload"}, 400
+        except EventNotFoundError as notFoundError:
+            logging.warning(notFoundError)
+            return {"message": f"Event {event_id} can not be found"}, 404
+        except Exception as ex:
+            logging.error(ex)
+            return {"message": "Unexpected error happened within the database"}, 500
+
 
     @requires_auth
     @is_user_or_has_role(None, UserType.ROOT_ADMIN)
diff --git a/exception/__init__.py b/exception/__init__.py
new file mode 100644
index 00000000..fd6bb24f
--- /dev/null
+++ b/exception/__init__.py
@@ -0,0 +1,2 @@
+from .client_exception import EventNotFoundError, InvalidArgumentError
+
diff --git a/exception/client_exception.py b/exception/client_exception.py
new file mode 100644
index 00000000..8b4d0acb
--- /dev/null
+++ b/exception/client_exception.py
@@ -0,0 +1,20 @@
+from .fireapp_exception import FireAppException
+
+
+class EventNotFoundError(FireAppException):
+    def __init__(self, event_id, *args):
+        super().__init__(f"Event not found", *args)
+        self.event_id = event_id
+
+    def __str__(self):
+        # Optionally customize the string representation for this specific error
+        return f"{self.message}: Event ID {self.event_id} could not be located."
+
+
+class InvalidArgumentError(FireAppException):
+    def __init__(self, *args):
+        super().__init__(f"Invalid argument(s)", *args)
+
+    def __str__(self):
+        # Optionally customize the string representation for this specific error
+        return f"{self.message}: unexpected values in the payload"
diff --git a/exception/database_exception.py b/exception/database_exception.py
new file mode 100644
index 00000000..e69de29b
diff --git a/exception/fireapp_exception.py b/exception/fireapp_exception.py
new file mode 100644
index 00000000..f1a99c1c
--- /dev/null
+++ b/exception/fireapp_exception.py
@@ -0,0 +1,3 @@
+class FireAppException(Exception):
+    pass
+
diff --git a/repository/volunteer_unavailability_v2.py b/repository/volunteer_unavailability_v2.py
index b36cc0fd..1f011ed6 100644
--- a/repository/volunteer_unavailability_v2.py
+++ b/repository/volunteer_unavailability_v2.py
@@ -2,37 +2,36 @@
 
 from flask import jsonify
 
-from datetime import datetime
-
+from datetime import datetime, timezone
+from exception import EventNotFoundError, InvalidArgumentError
 from domain import UnavailabilityTime, session_scope
 
 
-
 class EventRepository:
     def __init__(self):
         pass
 
-    def edit_event(self, userId, eventId, title=None, start=None, end=None, periodicity=None):
-        with session_scope() as session:
-            try:
-                event = session.query(UnavailabilityTime).filter(UnavailabilityTime.eventId == eventId,
-                                                                 UnavailabilityTime.userId == userId).first()
-                if event is None:
-                    return False
-                if title is not None:
-                    event.title = title
-                if start is not None:
-                    event.start = start
-                if end is not None:
-                    event.end = end
-                if end is not None:
-                    event.periodicity = periodicity
-                session.commit()
-                return True
-            except Exception as e:
-                session.rollback()
-                logging.error(e)
-                return None
+    def edit_event(self, session, userId, eventId, title=None, start=None, end=None, periodicity=None):
+        now = datetime.now(timezone.utc)
+        event = session.query(UnavailabilityTime).filter(UnavailabilityTime.eventId == eventId,
+                                                         UnavailabilityTime.userId == userId).first()
+        if event is None:
+            raise EventNotFoundError(eventId)
+        # validate user input
+        if start is not None and start < now:
+            raise InvalidArgumentError()
+        if end is not None and (end < now or end < start):
+            raise InvalidArgumentError()
+        # Edit fields with new values
+        if title is not None:
+            event.title = title
+        if start is not None:
+            event.start = start
+        if end is not None:
+            event.end = end
+        if end is not None:
+            event.periodicity = periodicity
+        session.commit()
 
     def get_event(self, userId):
         """
@@ -121,4 +120,4 @@ def check_overlapping_events(self, userId, startTime, endTime, periodicity):
                     # Add any other attributes you need
                 })
 
-        return overlapping_details
\ No newline at end of file
+        return overlapping_details