A power-saving synchronization of refresh requesting messages transmitted from a client terminal (31) to different server terminals (33a, 33b) in multiple soft-state dialogues, e.g. in SIP. The synchronization involves a continuous detection of a large time offset (34) occurring between the refresh requesting messages in the different dialogues, and an adjustment of the negotiated length of the refresh interval indicated in the refresh requesting messages, such that the client terminal will transmit the refresh requesting messages approximately simultaneously to the different server terminals.