(a) The court may correct an illegal sentence at any time while the defendant is serving such sentence. The defendant shall receive full credit for time spent in custody under the sentence prior to correction. Unless the motion and the files and records of the case conclusively show that the defendant is entitled to no relief, the defendant shall have a right to a hearing, after reasonable notice to be fixed by the court, to be personally present and to have the assistance of counsel in any proceeding for the correction of an illegal sentence.
(b) Clerical mistakes in judgments, orders or other parts of the record and errors in the record arising from oversight or omission may be corrected by the court at any time and after such notice, if any, as the court orders.
(c) For the purposes of this section:
(1) "Illegal sentence" means a sentence: Imposed by a court without jurisdiction; that does not conform to the applicable statutory provision, either in character or punishment; or that is ambiguous with respect to the time and manner in which it is to be served at the time it is pronounced. A sentence is not an "illegal sentence" because of a change in the law that occurs after the sentence is pronounced.
(2) "Change in the law" means a statutory change or an opinion by an appellate court of the state of Kansas, unless the opinion is issued while the sentence is pending an appeal from the judgment of conviction.
(d) The amendments made to this section by this act are procedural in nature and shall be construed and applied retroactively.