Changing business environments are forcing organizations to develop flexible and adaptable enterprise systems. To accomplish this and to solve associated systems integration issues, many are moving towards web service technology. Two key ingredients of web services based solution are service composition and service choreography. While there has been lot of advancement in respect to service composition, service choreography rather largely remains an open problem. WS-CDL specification is considered to be a candidate standard for service choreography; however, consensus on support mechanisms to develop conversation models depicting peer-to-peer interactions are yet to be reached. In this paper, we develop an approach as well required heuristics for identifying service interaction patterns from business process models and using them to develop conversation models. We provide detailed discussion on heuristics, illustrate our approach through an example, as well as indicate how these conversation models can be used for generating WS-CDL specifications.