A system and method for applying a communication feature extension includes facilitating an exchange of requests between an originating endpoint and a terminating endpoint using a first identifier associated with the originating endpoint and a second identifier associated with the terminating endpoint. A modified request is received during the exchange. The modified request includes a new identifier representing a selected one of a modified first identifier and a modified second identifier, and an extension providing information about handling the modified request. The extension included in the modified request is determined and applied.