Neb. Rev. Stat. § 72-240.25: Neb. Rev. Stat. § 72-240.25

Any lessee of educational lands may, subject to the approval of the board, relinquish his interest in such lease as of the following December 31 by notice to the Board of Educational Lands and Funds on or before November 30 of that year. The notice must be in writing signed and acknowledged by the lessee, and delivered to the office of the board.