The vice chief is the principal deputy of the chief of Naval operations (CNO). The vice chief may also perform other delegated duties that either the secretary of the Navy or the CNO assigns to him or her. In the event that the CNO is absent or is unable to perform their duties, the vice chief assumes the duties and responsibilities of the CNO. Within the Office of the Chief of Naval Operations, while there are several Deputy Chiefs of Naval Operations (DCNOs) of either three or two star rank, there is only one VCNO.