The present invention relates to a method, system, client device, conference server device and computer program product of controlling media composition in a multi-party conversation involving a central control point (50). At a participant (10) of said multi-party conversation, a scope information (SoM) which specifies members of said multi-party conversation is selected and added to a session modifying request. The session modifying request is transmitted to the central control point (50) which initiates a media modification at the specified members in response to the scope information (SoM). Thereby, a client can control whether media modification is applied to the whole conference, selected participants or only between the client itself and the conference server.