In the field of access control, delegation is an important aspect that is considered as a part of the administration mechanism. Thus, a complete access control must provide a flexible administration model to manage delegation. Unfortunately, to our best knowledge, there is no complete model for describing all delegation requirements for rolebased access control. Therefore, proposed models are often extended to consider new delegation characteristics, which is a complex task to manage and necessitate the redefinition of these models. In this paper we describe a new delegation approach for extended role-based access control models. We show that our approach is flexible and is sufficient to manage all delegation requirements.