Neb. Rev. Stat. § 76-246: Conveyances; power of attorney; how revoked.

No instrument containing a power to convey, or in any manner to affect real estate, executed, acknowledged or proved, and certified and recorded in conformity with the requirements of sections 76-211 to 76-245 and 76-2,126, can be revoked by any act of the party or parties thereto until the instrument of revocation is executed, acknowledged or proved, and certified and filed for record with the register of deeds of the county in which the power is recorded.