To override the Content-type in your clients, use the HTTP Accept Header, append  the .xml suffix or  ?format=xml
 
		
        
        HTTP + XML
         The following are sample HTTP requests and responses. 
            The placeholders shown need to be replaced with actual values.
POST /DynamicsCRM/List/{guid} HTTP/1.1 
Host: data.regent-college.edu 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<CRMListRequest xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/regis.DynamicsCRM.Requests">
  <guid>String</guid>
</CRMListRequest>
 
HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: length
<ArrayOfstring xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays">
  <string>String</string>
</ArrayOfstring>