Okla. Stat. tit. 12, § 12-1148.6: Answer or affidavit by defendant

A. In all cases in which the defendant wishes to assert title

to the land or that the boundaries of the land are in dispute, he

shall, before the time for the trial of the cause, file a verified

answer or an affidavit which contains a full and specific statement

of the facts constituting his defense of title or boundary dispute.

If the defendant files such a verified answer or affidavit, the

action shall proceed as one in ejectment before the proper division

of the district court. If the defendant files an affidavit he shall

file answer within ten (10) days after the date the affidavit is

filed.

B. In all cases in which the cause of action is based on an

asserted breach of a lease by the defendant, or the termination or

expiration of a lease under which the defendant claims an interest

in the property in a verified answer or affidavit, the plaintiff may

proceed with the forcible entry and detainer action instead of an

ejectment action.

C. No answer by the defendant shall be required before the time

for trial of the cause.