Okla. Stat. tit. 12, § 12-1145
Recovery where plaintiff's right ceases during action
In an action for the recovery of real property, where the
plaintiff shows a right to recover at the time the action was
commenced, but it appears that his right has terminated during the
pendency of the action, the verdict and judgment must be according
to the fact, and the plaintiff may recover for withholding the
property.
R.L. 1910, § 4931.