Using the Centralized Attendant Service (CAS) feature, attendants within a private network can serve all branch locations from a central or a main location. Each branch in a centralized attendant service has its own listed directory number (LDN) or other type of access from the public network. With this feature, the system routes incoming calls to a branch, and calls that users make directly to the attendants, to the centralized attendant. CAS uses release link trunks (RLT) to direct calls.