A Software Development Process for a certain enterprise and/or a certain project will usually integrate elements from a variety of existing process models, comprising generic standards as well as specific development methods. Besides that, change and evolution of business and technology imply change and evolution of development processes. In this paper we propose a Process Framework, which is modularly structured, and define the concept of process patterns. This framework allows us to describe development processes in such a way that integration, change and evolution of processes are facilitated. An example illustrates our approach.