An approach for processing voice calls over a packet switched network as to efficiently utilize the functionalities of a Voice Response Unit (VRU). According to one embodiment, a call originator, acting as a User Agent Client in accordance with the Session Initiation Protocol (SIP), issues messages to establish a first call-leg with the VRU. The VRU performs digit collection to obtain information to authenticate the call originator and to authorize the voice call. Based upon the issued messages from the call originator, the VRU establishes a second call-leg with the call terminator. The VRU is released from the voice call after binding the call-legs to connect the call originator to the call terminator.