Okla. Stat. tit. 58, § 58-555: Contest by heirs

All matters, including allowed claims not passed upon on the

settlement of any former account, or on rendering an exhibit, or on

making a decree of sale, may be contested by the heirs for cause

shown. The hearing and allegations of the respective parties may be

postponed from time to time, when necessary, and the court may

appoint one or more referees to examine the account and make report

thereon, subject to confirmation; and may allow a reasonable

compensation to the referees, to be paid out of the estate of the

decedent.