To override the Content-type in your clients, use the HTTP Accept Header, append  the .csv suffix or  ?format=csv
        
        HTTP + CSV
         The following are sample HTTP requests and responses. 
            The placeholders shown need to be replaced with actual values.
POST /api/contacts/change-alert HTTP/1.1 
Host: cpo.hostedsuite.com 
Accept: text/csv
Content-Type: text/csv
Content-Length: length
{"ContactId":"String","Alert":"String","CustomerName":"String","UserName":"String","Password":"String"}
 
HTTP/1.1 200 OK
Content-Type: text/csv
Content-Length: length
{}