3.9.5.4 Error Responses
The server MUST send back a 400 Bad Request response if the XML body is not a valid http://schemas.microsoft.com/2006/09/sip/roaming-self document.
The server MUST send back a 400 Bad Request response if the delegator URI is identical to the delegate uri specified in the request.
The server SHOULD send back a 403 Forbidden response if the From-URI and the To-URI are not identical.<48>
The server MUST send back a 403 Forbidden response if the action is "remove" and the delegate is not found in the delegateSet of the delegator.
The server MUST send back a 404 Not Found if the delegate specified in the request is not a valid URI in this deployment.
The server MUST send back a 409 Conflict response if the version check fails. The format of this message is specified in section 2.2.2.10.4.
The server MUST send back a 413 Request Entity Too Large response if the request is being denied because it caused the delegate quota to be exceeded.