Okla. Stat. tit. 59, § 1112

After the expiration of one (1) year after the Department denies an application for certification, renewal or reactivation or revokes a certificate pursuant to the Waterworks and Wastewater Works Operator Certification Act, the holder of such certificate may make application to the Department for renewal, reactivation or reinstatement. Such renewal, reactivation or reinstatement shall rest in the sound discretion of the Department.