One of the most remarkable aspect about service businesses is value cocreation. The service product/process is co-created by the customer and service provider together. Thus, from the service provider’s perspective, it is critical to effectively and efficiently manage the participation of customers in service design and delivery. This paper provides a theoretical model of the relationship between service modularity and effective customer participation/roles in service generation process, leading to better service firm performance. Moderation effect of customer training and education in the above relationship is also theorized. Using role theory and customer readiness model, various propositions are made to be tested in future.