GetChanges - AssignmentAdd

GetChanges API return the following change object when adding a user to a folder, list or web (AssignmentAdd corresponds to ChangeType=11)

It returns the webId, listId and itemId. But how to find which User or group got add to the item, folder or web?

      {"__metadata": {"id": "https://veraengenv.sharepoint.com/_api/SP.ChangeIteme8e7c72e-351c-405e-af8b-fd7d079bb19d","uri": "https://veraengenv.sharepoint.com/_api/SP.ChangeIteme8e7c72e-351c-405e-af8b-fd7d079bb19d","type": "SP.ChangeItem"
        },"ChangeToken": {"__metadata": {"type": "SP.ChangeToken"
          },"StringValue": "1;1;82f899bd-d9f3-4180-9f45-615061b8a1ea;636171383265830000;94119791"
        },"ChangeType": 11,"SiteId": "82f899bd-d9f3-4180-9f45-615061b8a1ea","Time": "2016-12-12T11:18:46.583Z","Editor": "","EditorEmailHint": null,"ItemId": 15,"ListId": "e3b1e975-ebd0-40c3-be1b-66dd68207b3a","ServerRelativeUrl": "","SharedByUser": null,"SharedWithUsers": null,"WebId": "e8a4668d-4472-48cf-8e00-7330f284de8c"
      }