N.Y.C. Admin. Code § 28-408.4.4: § 28-408.4.4 Failure to obtain seal.

If a holder of a certificate of competence has held the certificate for five (5) years without a seal, then the commissioner may require said person to submit an affidavit and supporting documentation satisfactory to the department stating that over the five (5) year period the individual has been engaged in the installation of plumbing systems and the planning or the design of plumbing systems in the United States under the direct and continuing supervision of a licensed master plumber. If the holder's qualifications are not satisfactory to the commissioner, the commissioner may require such person to submit to reexamination or to provide evidence of retained proficiency. Additional fees will be due, as set forth in this chapter.