Section 44.52 - Revocation of modification(a)Petition for revocation. Any party to a proceeding under this part in which a petition for modification of a mandatory safety standard was granted by an Administrator, administratior law judge, or the Assistant Secretary may petition that the modification be revoked. Such petition shall be filed with the Chief Administrative Law Judge for disposition.(b)Revocation by the Administrator. The appropriate Administrator may propose to revoke a modification previously granted by the Administrator, an administrative law judge, or the Assistant Secretary, by issuing a proposed decision and order revoking the modification. Such proposed revocation and a statement of reasons supporting the proposal must be served upon all parties to the proceeding, and shall become final on the 30th day after service thereof unless a hearing is requested in accordance with § 44.14 .(c) Revocation of a granted modification must be based upon a change in circumstances or because findings which originally supported the modification are no longer valid.(d) Disposition of the revocation shall be subject to all procedures of subparts C through E of this part.55 FR 53443, Dec. 28, 1990