A computer workstation-associated call handler uses hooking and sub-classing techniques to modify actions executed by an underlying call handler application program to automatically trigger various call handler actions. These actions may include playback of pre-recorded personal response type phrases or other pre-defined actions at various instances during a call, in response to the call agent's interactions with personalized response system-based, and forms-based software in the course of servicing telephone calls. This obviates the need to change the source code of the target application.