46 C.F.R. § 67.149
(a) When exchange of a Certificate of Documentation issued to a vessel is required pursuant to subpart L of this part and the vessel is at sea, the owner may affect the exchange while the vessel is still at sea by:
Note: A Certificate of Documentation is issued upon compliance with the applicable requirements, however, the requirement to mark the vessel with its new name or hailing port in accordance with subpart I of this part, if applicable, is waived until the vessel reaches its first port of call, wherever that may be.
[CGD 89-007, CGD 89-007a, 58 FR 60266, Nov. 15, 1993, as amended by CGD 95-014, 60 FR 31604, June 15, 1995; USCG-2006-25556, 72 FR 36330, July 2, 2007]