BPEL is the most popular language for describing business process and business interaction based on Web services for inter-organizational cooperation. Nevertheless, BPEL requires a static binding of services to the flows. We propose in this paper a new approach enabling dynamic binding. This approach consists of, first, providing a high-level description of process, second, abstracting the process behavior using symbolic observation graphs and third providing an efficient algorithm for symbolic observation graphs matching which is used for binding dynamically business processes.