The invention relates to session control in an IMS domain of a communications network and more particularly to techniques for performing session transfer in an IMS control node (SCC AS) for controlling centralized services in an IMS domain. One embodiment of an SCC AS (200) may be adapted to store, for each of a plurality of ongoing communication sessions, a session information item (218) comprising a user identity (222) identifying a user device involved in the session and a first identifier (216) of the user device in a CS domain of the communications network, wherein the user identity is associated with multiple user devices and the first identifier comprises at least one of an MSISDN (216), an IMSI, and a GRUU.