((a)) Any person may, within five years after the issuance of a certificate of plant variety protection, notify the Secretary in writing of facts which may have a bearing on the protectability of the variety, and the Secretary may cause such plant variety protection to be reexamined in the light thereof.

((b)) Reexamination of plant variety protection under this section and appeals shall be pursuant to the same procedures and with the same rights as for original examinations. Abandonment of the procedure while subject to a ruling against the retention of the certificate shall result in cancellation of the plant variety certificate thereon and notice thereof shall be endorsed on copies of the description of the protected plant variety thereafter distributed by the Plant Variety Protection Office.

((c)) If a person acting under subsection (a) makes a prima facie showing of facts needing proof, the Secretary may direct that the reexamination include such interparty proceedings as the Secretary shall establish.