In this paper, we introduce an agent planner architecture that can reduce the basic artifacts of agent planning paradigms, semantic services and business process languages into a common workflow model. These artifacts are then executed by means of a workflow component that the architecture includes. By having a workflow component in an agent infrastructure, various agent programming paradigms including different planning approaches as well as different workflow definition languages can be executed on the same agent platform. To illustrate our ideas, we focus on the reduction of plans to the workflow model. To explicate the reduction mechanism, we have preferred to use HTN which is a widely known planning approach in multi-agent domain. Based on the semantics that we have defined for our workflow and HTN models, we have given an algorithm for transformation from HTN to workflow model.