37 C.F.R. § 1.550 : Patents, Trademarks, and Copyrights — UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE — GENERAL — RULES OF PRACTICE IN PATENT CASES — EX PARTE REEXAMINATION OF PATENTS —EX PARTE REEXAMINATION — Conduct of ex parte reexamination proceedings

(a) All ex parte reexamination proceedings, including any appeals to the Board of Patent Appeals and Interferences, will be conducted with special dispatch within the Office. After issuance of the ex parte reexamination order and expiration of the time for submitting any responses, the examination will be conducted in accordance with §§1.104 through 1.116 and will result in the issuance of an ex parte reexamination certificate under §1.570.
(b) The patent owner in an ex parte reexamination proceeding will be given at least thirty days to respond to any Office action. In response to any rejection, such response may include further statements and/or proposed amendments or new claims to place the patent in a condition where all claims, if amended as proposed, would be patentable.
(c) The time for taking any action by a patent owner in an ex parte reexamination proceeding may be extended as provided in this paragraph.
(1) Any request for such an extension must specify the requested period of extension and be accompanied by the petition fee set forth in §1.17(g).
(2) Any request for an extension in a third party requested ex parte reexamination must be filed on or before the day on which action by the patent owner is due, and the mere filing of such a request for extension will not effect the extension. A request for an extension in a third party requested ex parte reexamination will not be granted in the absence of sufficient cause or for more than a reasonable time.
(3) Any request for an extension in a patent owner requested or Director ordered ex parte reexamination for up to two months from the time period set in the Office action must be filed no later than two months from the expiration of the time period set in the Office action. A request for an extension in a patent owner requested or Director ordered ex parte reexamination for more than two months from the time period set in the Office action must be filed on or before the day on which action by the patent owner is due, and the mere filing of a request for an extension for more than two months from the time period set in the Office action will not effect the extension. The time for taking action in a patent owner requested or Director ordered ex parte reexamination will not be extended for more than two months from the time period set in the Office action in the absence of sufficient cause or for more than a reasonable time.
(4) The reply or other action must in any event be filed prior to the expiration of the period of extension, but in no situation may a reply or other action be filed later than the maximum time period set by statute.
(5) See §90.3(c) of this title for extensions of time for filing a notice of appeal to the U.S. Court of Appeals for the Federal Circuit or for commencing a civil action.
(d) If the patent owner fails to file a timely and appropriate response to any Office action or any written statement of an interview required under §1.560(b), the prosecution in the ex parte reexamination proceeding will be a terminated prosecution, and the Director will proceed to issue and publish a certificate concluding the reexamination proceeding under §1.570 in accordance with the last action of the Office.
(e) If a response by the patent owner is not timely filed in the Office, a petition may be filed pursuant to §1.137 to revive a reexamination prosecution terminated under paragraph (d) of this section if the delay in response was unintentional.
(f) The reexamination requester will be sent copies of Office actions issued during the ex parte reexamination proceeding. After filing of a request for ex parte reexamination by a third party requester, any document filed by either the patent owner or the third party requester must be served on the other party in the reexamination proceeding in the manner provided by §1.248. The document must reflect service or the document may be refused consideration by the Office.
(g) The active participation of the ex parte reexamination requester ends with the reply pursuant to §1.535, and no further submissions on behalf of the reexamination requester will be acknowledged or considered. Further, no submissions on behalf of any third parties will be acknowledged or considered unless such submissions are:
(1) in accordance with §1.510 or §1.535; or
(2) entered in the patent file prior to the date of the order for ex parte reexamination pursuant to §1.525.
(h) Submissions by third parties, filed after the date of the order for ex parte reexamination pursuant to §1.525, must meet the requirements of and will be treated in accordance with §1.501(a).
(i) A petition in an ex parte reexamination proceeding must be accompanied by the fee set forth in §1.20(c)(6), except for petitions under paragraph (c) of this section to extend the period for response by a patent owner, petitions under paragraph (e) of this section to accept a delayed response by a patent owner, petitions under §1.78 to accept an unintentionally delayed benefit claim, and petitions under §1.530(l) for correction of inventorship in a reexamination proceeding.

37 C.F.R. §1.550

65 FR 76776, 12/7/2000, as amended at 69 FR 56545, 9/21/2004; 72 FR 18905, 4/16/2007; 77 FR 48851, 8/14/2012; 78 FR 62407, 10/21/2013