Business processes are subject to changes due to frequently fluctuating opportunities. The changes has as result a modification of business process models and also the organizational model since both models are jointly linked through the assignment of roles to process activities. A consistent adaptation of both model types (due to changes) still poses challenges. For instance, varying competences and skills are insufficiently considered for the (re-)assignment of roles to process activities. As a consequence, tasks are performed inefficiently. In this paper we will present an organizational model that considers resources’ competences, skills and knowledge. Based on this model the hidden Markov model is applied to efficiently assign roles to process activities. The improvement in task processing through automated role assignment is a significant contribution of this approach.