— The en-route conflict resolution remains a major concern for Air Traffic Management (ATM), especially in core European airspace where the current Air Traffic Control (ATC) system is approaching its capacity limits. In this paper we discuss the emphasis of the coordination of conflict resolution actions. Indeed, coordination of conflict resolution is required to reach a global solution for clusters involving many aircraft. A number of such models have already been proposed and some of them applied in practice, but there has been no cohesive discussion or comparative evaluation of these approaches. This paper presents a summary of coordination of conflict resolution approaches.