Method and apparatus for transferring a call leg in a telecommunication
network and releasing it to free up resources, while allowing retrieval at
a later time under specified conditions. Message extensions are provided
for interfaces used between service nodes and host switches in a
telecommunication networks. The invention is appropriate for use in an
integrated services digital network (ISDN), in an internet protocol (IP)
telephony network, or in any other type of telecommunication network. The
service node sends a transfer request and retrieval conditions -to the
switch. The switch stores the conditions and transfers the channel with
the appropriate call leg, but can retrieve the call leg when one of the
conditions is met.