A supporting method of the evolution of state diagrams with scenarios

State diagram is one of the primary documents in software development. In software maintenance phase, system behaviors often change. In accordance with these changes, state diagrams should be correctly modified. However, it may be difficult to modify the state diagrams accurately. We propose a supporting method of state-diagram evolution using scenarios. The reason of focusing on scenarios is that scenarios are familiar and comprehensible to stakeholders. Our method is illustrated with an example.