Section 13.403 - [Effective 1/17/2025] Service requirements(a) Each applicant already holding an MMC endorsed as Tank Vessel-Assistant for DL and seeking one for LG, or the converse, must-(1) Provide evidence of at least half the service required in § 13.401(e)(2) and successfully complete a professional examination for the topics identified in table 1 to § 13.121(e) appropriate to the endorsement applied for; or(2) Complete a course in DL or LG appropriate to the endorsement applied for as prescribed in § 13.401(e)(1) .