The best-fit workflow management system architecture for the workflows in the internet is dependent on the workflow types that should be processed in the workflow system. Since a workflow management system should accommodate various kinds of workflows requiring different workflow system architecutres respectively as their best-fit workflow system architectures, it is ideal that a workflow system covers various workflow system architectures and changes its architecture according to the input workflow types. In this paper we propose a workflow system architecute that covers various workflow architecutres within a single workflow system. The system changes its architecture by creating an execution object for a task in the form of an object instance and placing the created object instance to anywhere the system wants to. Performance test has been performed on the early versions of the system changing its architectures, and the results are illustreated. The results show that the distributed multiple workflow servers in the internet can contribute to not only reliable control of the distributed tasks but also enhancing total throughput of a workflow system.