diff --git a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
index 8c8391c10e13..5c08c67b1472 100644
--- a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
+++ b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
@@ -65,7 +65,7 @@
       "properties": {
         "createdByCommunicationIdentifier": {
           "description": "The communication identifier of the user who created the thread",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "properties": {
           "description": "The thread properties",
@@ -93,7 +93,7 @@
       "properties": {
         "deletedByCommunicationIdentifier": {
           "description": "The communication identifier of the user who deleted the thread",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "deleteTime": {
           "description": "The deletion time of the thread",
@@ -112,7 +112,7 @@
       "properties": {
         "editedByCommunicationIdentifier": {
           "description": "The communication identifier of the user who updated the thread properties",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "editTime": {
           "description": "The time at which the properties of the thread were updated",
@@ -143,7 +143,7 @@
         },
         "addedByCommunicationIdentifier": {
           "description": "The communication identifier of the user who added the user",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "participantAdded": {
           "description": "The details of the user who was added",
@@ -166,7 +166,7 @@
         },
         "removedByCommunicationIdentifier": {
           "description": "The communication identifier of the user who removed the user",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "participantRemoved": {
           "description": "The details of the user who was removed",
@@ -257,7 +257,7 @@
         },
         "senderCommunicationIdentifier": {
           "description": "The communication identifier of the sender",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "senderDisplayName": {
           "description": "The display name of the sender",
@@ -285,7 +285,7 @@
       "properties": {
         "recipientCommunicationIdentifier": {
           "description": "The communication identifier of the target user",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         },
         "transactionId": {
           "description": "The transaction id will be used as co-relation vector",
@@ -307,7 +307,7 @@
         },
         "participantCommunicationIdentifier": {
           "description": "The communication identifier of the user",
-          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+          "$ref": "#/definitions/CommunicationIdentifier"
         }
       }
     },
@@ -347,6 +347,14 @@
           "type": "integer"
         }
       }
+    },
+    "CommunicationIdentifier": {
+      "description": "Schema of the CommunicationIdentifier object used to identify an ACS user",
+      "allOf": [
+        {
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        }
+      ]
     }
   }
 }