IP Multimedia Subsystem (IMS) has been widely accepted by telecom industry as a prolific platform for providing next generation Telecom services, and massive deployment has been finally taking off. However, most of the services in IMS environment are still developed in silo method which makes new services implementation to be a time-consuming and burdensome process. In this paper, we consider service composition as an alternative approach for rapid service creation, reusing service capabilities to implement new services. For this goal, we analyze existing standards for IMS service composition management, and show how the Service Capability Interaction Manager (SCIM) is used for brokering services capabilities and managing service composition. Based on this analysis, we propose a SCIM-based architecture evolution in order to enable an agile service composition.