47 CFR § 13.11 - Holding more than one commercial radio operator license.
(a) An eligible person may hold more than one commercial operator license.
(1) No person may hold two or more unexpired radiotelegraph operator's certificates at the same time;
(2) No person may hold any class of radiotelegraph operator's certificate and a Marine Radio Operator Permit;
(3) No person may hold any class of radiotelegraph operator's certificate and a Restricted Radiotelephone Operator Permit.
(b) Each person who is not legally eligible for employment in the United States, and certain other persons who were issued permits prior to September 13, 1982, may hold two Restricted Radiotelephone Operator Permits simultaneously when each permit authorizes the operation of a particular station or class of stations.