Methods and apparatus are disclosed for a wireless transmit/receive unit (WTRU) to request collaborative session control transfer for transferring control of an Internet Protocol (IP) multimedia subsystem (IMS) collaborative session from a controller WTRU to another WTRU, such as a controllee WTRU. The collaborative session control transfer request is sent to an IMS Service Centralization and Continuity Application Server (SCC AS). Methods and apparatus are also disclosed for a WTRU to request inter device transfer (IDT) for transferring an IMS collaborative session media session flow from one WTRU to another WTRU.