Okla. Stat. tit. 58, § 58-129: Contest of petition - Notice

Any person interested may contest the petition by filing written

opposition thereto, on the ground of the incompetency of the

applicant, or may, at any time within thirty (30) days after an

administrator has been appointed, assert his own rights to the

administration and pray that letters be issued to himself. In the

latter case the contestant must file his petition in the court. The

court thereof shall set a day for hearing the same and the

contestant shall give written notice by mail, postage prepaid, to

the known heirs and the original petitioner or administrator, if the

appointment has been made, of said contest, and the time and place

set for hearing the same, at least five (5) days before said

hearing.