Okla. Stat. tit. 12, § 1033

If more than thirty (30) days after a judgment, decree, or appealable order has been filed, proceedings to vacate or modify the judgment, decree, or appealable order, on the grounds mentioned in paragraphs 2, 4, 5, 6, 7, 8, and 9 of Section 1031 of this title, shall be by petition, verified by affidavit, setting forth the judgment, decree, or appealable order, the grounds to vacate or modify it, and the defense to the action, if the party applying was defendant. On this petition, a summons shall issue and be served as in the commencement of a civil action.