(A) Certificates which shall have been suspended or revoked by the Board shall be returned to the city and the operation of any taxicab authorized covered by the certificate shall cease.
(B) Any owner who shall permanently retire any taxicab or taxicabs from taxicab service and not replace same within 30 days thereof, shall immediately surrender the certificate granted for the taxicab to the Board and may not secure additional certificates for operation of taxicabs without having first made application therefor in the manner provided in this chapter.
(`86 Code, § 19-35)