A person can move to modify a sentence within sixty (60) days of the sentence, or within 60 days of a lost appeal.
RULE 3.800. CORRECTION, REDUCTION, AND MODIFICATION OF SENTENCES (c) Reduction and Modification. A court may reduce or modify to include any of the provisions of chapter 948, Florida Statutes, a legal sentence imposed by it, sua sponte, or upon motion filed within 60 days after the imposition, or within 60 days after receipt by the court of a mandate issued by the appellate court on affirmance of the judgment and/or sentence on an original appeal, or within 60 days after receipt by the court of a certified copy of an order of the appellate court dismissing an original appeal from the judgment and/or sentence, or, if further appellate review is sought in a higher court or in successively higher courts, within 60 days after the highest state or federal court to which a timely appeal has been taken under authority of law, or in which a petition for certiorari has been timely filed under authority of law, has entered an order of affirmance or an order dismissing the appeal and/or denying certiorari. If review is upon motion, the trial court shall have an additional 60 days or additional time as agreed by the parties to file an order ruling on the motion. This subdivision shall not be applicable to those cases in which the death sentence is imposed or those cases in which the trial judge has imposed the minimum mandatory sentence or has no sentencing discretion.