Okla. Stat. tit. 12, § 1840

Parties - Selection and compensation of mediators. Nothing in the Choice in Mediation Act shall limit the ability of parties to a dispute to select and, if appropriate, compensate a mediator of their choice, whether or not that mediator is certified under the Dispute Resolution Act or qualified under the District Court Mediation Act; nor shall anything in the Choice in Mediation Act prohibit any person from acting as a mediator of a dispute when so requested by the parties to the dispute.