A motion to vacate judgment refers to a request that is filed before the court that entered the judgment to dismiss the judgment. Law prescribes specific time line and grounds for filing such motions. There are state specific laws on the subject which vary from state to state.
Example of a State Statute on Motion to Vacate Judgment or Sentence.
In Florida as per the Civil Procedure Code a party may file motion to vacate judgment or any other proceeding for the following reasons
The motion should be filed within a reasonable time. Filing of the motion does not affect the finality of a judgment or decree or suspend its operation.
Relevant portion of the law as it appears in the statute
Fla. R. Civ. P. 1.540. Relief from Judgment, Decrees or Orders
(b) Mistakes; Inadvertence; Excusable Neglect; Newly Discovered Evidence; Fraud; etc. --On motion and upon such terms as are just, the court may relieve a party or a party's legal representative from a final judgment, decree, order, or proceeding for the following reasons:
(1) mistake, inadvertence, surprise, or excusable neglect;
(2) newly discovered evidence which by due diligence could not have been discovered in time to move for a new trial or rehearing;
(3) fraud (whether heretofore denominated intrinsic or extrinsic), misrepresentation, or other misconduct of an adverse party;
(4) that the judgment or decree is void; or
(5) that the judgment or decree has been satisfied, released, or discharged, or a prior judgment or decree upon which it is based has been reversed or otherwise vacated, or it is no longer equitable that the judgment or decree should have prospective application.
The motion shall be filed within a reasonable time, and for reasons (1), (2), and (3) not more than 1 year after the judgment, decree, order, or proceeding was entered or taken, except that there shall be no time limit for motions based on fraudulent financial affidavits in marital cases. A motion under this subdivision does not affect the finality of a judgment or decree or suspend its operation. This rule does not limit the power of a court to entertain an independent action to relieve a party from a judgment, decree, order, or proceeding or to set aside a judgment or decree for fraud upon the court.