Workflow management, one of the important technologies for supporting collaborative work, requires database technologies like distributed data management or transaction management. However, as workflow management systems have several heterogeneities like heterogeneity about agents, spatial heterogeneity, temporal heterogeneity, etc., collaboration model for workflow management should resolve these heterogeneities. In this paper, we propose a collaboration model for workflow management using a heterogeneous distributed problem solver Helios. Agents, environments in which agents coordinate each other, and coordination among agents are modeled by message passing among agents. These modeling give semantics of agents in Workflow Base, previously proposed formal workflow database model based on object-oriented data model, as coordination entities.