Line appearance reservation for SIP endpoints

In one embodiment, a communication device includes an outgoing call alerting agent that (i) detects that a communication device has entered an off-hook state and that a first line appearance has been selected by a user for an outgoing call, (ii) forwards a first call setup message to a third party call controller, the call setup message including a request to reserve the first line appearance for the outgoing call, and (iii) thereafter collects a set of digits dialed by the user for the outgoing call and provides the collected set of digits to the third party call controller.