Okla. Admin. Code § 255:10-5-1
Pursuant to Title 68, Section 2464, in any case where the Board has increased the valuation of the property, or any class thereof, in any county, the Board shall notify by mail the Board of County Commissioners and the county assessor of said county, giving the amount of such valuation as increased. Either the District Attorney, acting under the direction of the Board of County Commissioners and for the entire taxpaying public of the county, or any taxpayer who might feel aggrieved at the change in the equalized value of his property, shall have ten (10) days from date of such notice in which to file with the Secretary of the Board written complaint specifying his grievances and the pertinent facts in relation thereto in ordinary and concise language and without repetition, and in such manner as to enable a person of common understanding to know what is intended.
Okla. Admin. Code § 255:10-5-1