diff --git a/specification/apimanagement/resource-manager/Microsoft.ApiManagement/preview/2019-12-01-preview/apimdeployment.json b/specification/apimanagement/resource-manager/Microsoft.ApiManagement/preview/2019-12-01-preview/apimdeployment.json
index 5ce734172f94..fa820c5a0170 100644
--- a/specification/apimanagement/resource-manager/Microsoft.ApiManagement/preview/2019-12-01-preview/apimdeployment.json
+++ b/specification/apimanagement/resource-manager/Microsoft.ApiManagement/preview/2019-12-01-preview/apimdeployment.json
@@ -1462,21 +1462,10 @@
           "description": "The client tenant id of the identity."
         },
         "userAssignedIdentities": {
+          "description": "The list of user identities associated with the resource. The user identity \r\ndictionary key references will be ARM resource ids in the form: \r\n'/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/\r\n    providers/Microsoft.ManagedIdentity/userAssignedIdentities/{identityName}'.",
           "type": "object",
           "additionalProperties": {
-            "type": "object",
-            "properties": {
-              "principalId": {
-                "readOnly": true,
-                "type": "string",
-                "description": "The principal id of user assigned identity."
-              },
-              "clientId": {
-                "readOnly": true,
-                "type": "string",
-                "description": "The client id of user assigned identity."
-              }
-            }
+            "$ref": "#/definitions/UserIdentityProperties"
           }
         }
       },
@@ -1484,6 +1473,19 @@
         "type"
       ]
     },
+    "UserIdentityProperties": {
+      "type": "object",
+      "properties": {
+        "principalId": {
+          "description": "The principal id of user assigned identity.",
+          "type": "string"
+        },
+        "clientId": {
+          "description": "The client id of user assigned identity.",
+          "type": "string"
+        }
+      }
+    },
     "Operation": {
       "description": "REST API operation",
       "type": "object",