(a) Informal petition. Any interested person may file an informal petition to modify or vacate a final order at any time. Any such petition must be filed with the Administrator, be based on matters arising after the issuance of the final order, and set forth such matters, and the reasons or conditions relied on, with such particularity as is practicable. Any such informal petition will be handled as otherwise provided for an informal complaint.

(b) Formal motion. A final order may be modified or vacated at any time only upon filing of a formal motion by the Administrator. Such a motion may be filed on the initiative of the Administrator, on the basis of an informal petition, or by filing of an informal petition as a formal motion.

(c) Publication. If the modification or vacation sought would involve an increase of a rate or charge lawfully prescribed by the Secretary, or involve a rate or charge in addition to what is specified in the final order, or involve a regulation or practice so affecting such a rate or charge, the formal motion, or a summary thereof, will be published in the Federal Register, together with notice of the place, and the time by which, any interested person may file a written request to be heard.

(d) Proceedings. Proceedings upon such a formal motion will be as otherwise provided for a formal complaint.