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 /api/documents/{DocumentID}/wopipreviewurl HTTP/1.1 
Host: doapigw.baasbv.nl 
Accept: application/xml
Content-Type: application/xml
Content-Length: length
<GetDocumentUrl xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/IDB.API.DTO.Document.Operations">
  <DocumentID>00000000-0000-0000-0000-000000000000</DocumentID>
</GetDocumentUrl>
 
HTTP/1.1 200 OK
Content-Type: application/xml
Content-Length: length
<GetDocumentUrlResponse xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/IDB.API.DTO.Document.Operations">
  <IsSharePointOnlineDocument>false</IsSharePointOnlineDocument>
  <Url>String</Url>
</GetDocumentUrlResponse>