Section 10.233 - Obligations of the holder of a merchant mariner credential(a) The holder of a credential may not voluntarily part with it or place it beyond his or her personal control by pledging or depositing it with any other person, except as required by regulation or as necessary to safeguard the credential. If the holder violates this section, the Coast Guard may pursue suspension or revocation of the license, MMD, COR, or MMC under the provisions of part 5 of this chapter.(b) Whenever a mariner loses a credential, he or she must immediately report the loss to the Coast Guard. The report must be made in writing, giving the facts incident to its loss.(c) Invalid credentials must be returned to the Coast Guard. Upon written request, the Coast Guard will return the cancelled credential to the mariner.