REVOCATION.

SEC. 503. REVOCATION. The Secretary may revoke an endorsement issued under section502, after notice and an opportunity for public comment, if the Secretary determines that the employment of the vessel in the coastwise trade has substantially changed since the issuance of the endorsement, and— (1) the vessel is employed other than as a small passenger vessel or an uninspected passenger vessel; or (2) the employment of the vessel adversely affects— (A) United States vessel builders; or (B) the coastwise trade business of any person who employs vessels built in the United States.