Indiana Code Title 29. Probate § 29-1-1-21

Sec. 21. For illegality, fraud or mistake, upon application filed within one (1) year after the discharge of the personal representative upon final settlement, the court may vacate or modify its orders, judgments and decrees or grant a rehearing therein.  Before any such order, judgment or decree shall be vacated or modified, notice of such application and hearing shall be given to the personal representative and all interested persons as provided in section 12 of this chapter.  No vacation or modification under this section shall affect any right acquired by any innocent person in reliance upon any such previous order, judgment or decree.