Service-Oriented Computing (SOC) is believed to be prominent for the efficient and effective businesses development. However, current SOC technologies and standards are challenged by the changeful environment and user requirements. Concerns for runtime evolution are evoked to realize extensible and adaptive service-oriented applications. In this paper we argue that software architecture, esp. dynamic software architecture (DSA), should be used as a complement view for the commonly adopted workflow views in service composition. Furthermore, a novel reification mechanism for DSA is proposed to enable the runtime evolution of the architecture. A corresponding system named Artemis-ARC is implemented to support the development, execution and dynamic reconfiguration of service-oriented applications.