The dynamics and volunteer-based workforce characteristics of incident command systems raise a challenge to workflow management. Incident command systems must be able to adapt to the ever changing surroundings and tasks during an incident. Furthermore, during an incident, the majority of workers are volunteers that vary in their knowledge of the fundamentals of workflows. To address these challenges, we developed an intuitive, yet formal approach to workflow modeling, enactment and validation. On the other hand, Event-Driven Process Chains (EPC), an informal workflow engine, has been widely used for business process modeling. In this paper, we consider how to convert a workflow model built using EPC engine to a Workflow Intuitive Formal Approach (WIFA) model, so that the well-formedness of the workflow model can be formally verified. This also allows heterogeneous inter-organizational workflow interaction.