top-down approach for workflow design is proposed in the framework of Petri net theory. Simple but powerful refinement rules are proposed that guarantee soundness of the resulting workflow nets. The refinement process supports defining regions, which are parts of a workflow that correspond to logistically related items. To each region, certain exception handlers can be associated. Defining regions supports determining the impact areas of the unexpected events during workflow execution.<P>
No knowledge about Petri nets is assumed from the audience.
