Method and system for processing call change request in an internet protocol multimedia subsystem

A method for processing a call change request in a network entity in an Internet Protocol Multimedia Subsystem (IMS), comprising:

• receiving a call request message requesting a first call from a calling User Equipment (UE), storing call information and caller information included in the call request message, and forwarding the call request message to a called UE;
• acquiring, upon receipt of a call change request message requesting change of the first call to a second call from the called UE during the first call, the caller information of the calling UE using an old call information included in the call change request message and the stored call information;
• inserting the caller information in receiver information of the call change request message and delivering the call change request message with the caller information to the calling UE;
• and
• establishing the second call between the calling UE and the called UE by replacing the first call with the second call according to the call change request message.