It might be an idea to use re-invite or update as already suggested. Another thing to look at is the media transport adapter. http://trac.pjsip.org/repos/wiki/Media_Transport_Adapter This is a supported way to manipulate the SDP in the offer/answer handling. Take a look and see if implementing a thin adapter only manipulating the SDP might solve your problem. /Johan ________________________________ Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra pol?tica de env?o y recepci?n de correo electr?nico en el enlace situado m?s abajo. This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at: http://www.tid.es/ES/PAGINAS/disclaimer.aspx