Method and apparatus for detecting subscriber service address change

A method and apparatus for allowing VoIP service providers to detect service address changes of IP service subscribers are disclosed. Specifically, when a power cycle, e.g., powering off and on, of a particular VoIP endpoint device, such as a Terminal Adaptor (TA) or a soft phone client, is detected, a service provider may assume that the service address of the subscriber has changed. Therefore, appropriate actions can be taken by the service provider to obtain the latest service address from the subscriber to ensure accurate service address information is available, e.g., in support of an emergency call through the particular VoIP endpoint device.