Business processes consisting of component Web services are often executed in volatile environments where the quality of service parameters of the participating services might change during the execution of the business processes. Recently, research has been carried out on adapting composite Web service in volatile service-oriented computing environments. However, current approaches do not consider the internal logic of the business process and the impact of adaptation for a single service on the other component services. Other than quality of service parameters, effective adaptation requires specific information of the component services in terms of their position and interaction in the business process. The work reported in this paper is a first step in this direction. We present a novel approach to adaptation of Web service composition based on workflow patterns. This approach measures the value of changed information that updated services may potentially introduce in the business process. Experimental results show that our approach provides effective adaptation solutions by expanding the adaptation scope and considering the internal logic of business process.