Okla. Stat. tit. 12, § 12-1101: Offer to allow judgment to be taken

The defendant, in an action for the recovery of money only, may,

at any time before the trial, serve upon the plaintiff or his

attorney an offer, in writing, to allow judgment to be taken against

him for the sum specified therein. If the plaintiff accept the

offer and give notice thereof to the defendant or his attorney,

within five days after the offer was served, the offer, and an

affidavit that the notice of acceptance was delivered within the

time limited, may be filed by the plaintiff, or the defendant may

file the acceptance, with a copy of the offer, verified by

affidavit; and in either case, the offer and acceptance shall be

noted in the journal, and judgment shall be rendered accordingly. If

the notice of acceptance be not given in the period limited, the

offer shall be deemed withdrawn, and shall not be given in evidence

or mentioned on the trial. If the plaintiff fails to obtain

judgment for more than was offered by the defendant, he shall pay

the defendant's costs from the time of the offer.