Workflow management systems are becoming increasingly important in the automation of business processes. In order to ensure proper workflow execution, workflow policies must be specified with respect to users, roles, and tasks. In today's dynamic business environment, successful organizations must be able to respond to new customer demands and market opportunities with flexibility and speed. However, without systematic management of workflow policies, changes in organizational structure and process models can lead to inconsistent workflow specifications. Thus far, research in the change management of workflow policies has been scant. In this paper, we propose a logic-based approach to address this problem. Our contribution is three-fold: 1) a modeling language based on predicate logic is proposed, which is succinct and expressive enough to represent process model, organization model, and workflow polices; 2) workflow policy consistency in a dynamic changing environment is formally defined and analyzed based on the proposed language. 3) two algorithms are developed to check and enforce the policy consistency. To the best of our knowledge, this is the first work focuses on the formal analysis of workflow policy change management.