Collaborative, long-term processes with changing requirements occur in several domains. In design and manufacturing, we observed the following particular characteristics: the process models can be huge and contain longsome decisions while the time to market is tight. Furthermore, different types of products have to be considered. In this paper, we present an approach of new, flexible workflow technology that provides a solution for this: The ongoing workflows can be adapted by means of late-planning and ad-hoc changes. A suspension mechanism allows the workflow designers to modify parts of a workflow while the remainder of the workflow can continue to be executed. A case-based reasoning approach supports the reuse of past experience for this.