Url

http://battlelog.battlefield.com/bf3/comcenter/hideChat/{CID}/ (Constants.URL_CHAT_CLOSE)

Headers

X-Requested-With => XMLHttpRequest

Notes

CID is retrieved via API: Get chat with user X

Response

None at all. I think it throws a 500 if you mess it up, so take any status code 200's as signs of it going alright.