The reconfigurable composite services (CWSs) can repair itself if any execution problems occur, in order to complete successfully its own execution. The research problem in which we are interested in is how to ensure the correctness of reconfigurable CWSs.This paper proposes an incremental design approach for modeling and verifying reconfigurable CWSs by using Event-B. We start by abstractly specifying the main requirements of reconfigurable CWSs and then refining them through several steps by introducing the concept of dependencies and dynamic transactional patterns (DTPs) to model reconfigurable CWSs. The consistency of each model and the relationship between an abstract model and its refinements are obtained by formal proofs. Finally, we use ProB model-checker to trace possible design errors.