The SOA (Service Oriented Architecture) paradigm provides important advantages like interoperability, reusability and flexibility required in the area of business applications. In our research works, we focus on the use of SOA to implement inter-organizational workflows (IOWF). Our goal is to obtain IOWF models flexible enough in order to ease their adaptation at build-time and at runtime, because services are loosely coupled components, easily invoked and interoperable. This paper focuses on specific and well common IOWF-architectures defined in the literature; it deals with adaptation of IOWF process models obeying to these architectures. First, we define the concept of Service-Based Cooperation Pattern (SBCP) that supports service-based IOWF models meeting one of the specific architectures considered. Then, we state a set of recurrent operations of adaptation (attached to process and interaction aspects) that can be applied on service-based IOWF models, and we illustrate their implementation for IOWF models specified with BPEL.