The Attorney General, within thirty days after entry of a Regional Commissioner's decision, may request in writing that the National Appeals Board review such decision. Within sixty days of the receipt of the request the National Appeals Board shall, upon the concurrence of two members, affirm, modify, or reverse the decision, or order a rehearing at the institutional or regional level. The Attorney General and the prisoner affected shall be informed in writing of the decision, and the reasons therefor.
28 C.F.R. §2.54