Section 821.50 - Petition for rehearing, reargument, reconsideration or modification of an order of the Board(a)General. Any party to a proceeding may petition the Board for rehearing, reargument, reconsideration or modification of a Board order on appeal from a law judge's initial decision or order. An initial decision or appealable order of a law judge that has become final because no timely appeal was taken therefrom may not be the subject of a petition under this section.(b)Timing and service. The petition must be filed with the Board, and simultaneously served on the other parties, within 30 days after the date of service of the Board's order on appeal from the law judge's initial decision or order.(c)Content. The petition shall state briefly and specifically the matters of record alleged to have been erroneously decided, and the ground or grounds relied upon. If the petition is based, in whole or in part, upon new matter, it shall set forth such new matter and shall contain affidavits of prospective witnesses, authenticated documents, or both, or an explanation of why such substantiation is unavailable, and shall explain why such new matter could not have been discovered in the exercise of due diligence prior to the date on which the evidentiary record closed. To the extent the petition is not based upon new matter, the Board will not consider arguments that could have been made in the appeal or reply briefs received prior to the Board's decision.(d)Repetitious petitions. Repetitious petitions will not be entertained by the Board, and will be summarily dismissed.(e)Reply to petition. Any other party to the proceeding may file a reply to the petition within 15 days after the date on which the petition was served on that party. A copy of such reply shall simultaneously be served on the petitioner and any other parties to the proceeding.(f)Stay of effective date of Board's order. The filing of a petition under this section shall operate to stay the effective date of the Board's order, unless the Board directs otherwise. 68 FR 22625 , Apr. 29, 2003, as amended at 77 FR 63252 , Oct. 16, 2012