A method and apparatus for, upon generation of an event triggering a change in the state of a UE participating in a call, sending service information changed due to the state change to the other participating entity and notifying each user of the service information are provided. When a state change event occurs to a UE, the UE checks its available services and sends a message including service information indicating the available services to the other entity connected to the UE. Therefore, the other entity has knowledge of the actual available services of the UE in a changed environment.