Section 13.403 - Service requirements(a) Each applicant already holding an MMD or MMC endorsed tankerman-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) of this subpart and successfully complete a professional examination for the topics identified in Table 1 to § 13.121(e) of this part 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) of this subpart.USCG-2004-17914, 78 FR 77996, Dec. 24, 2013