Neb. Rev. Stat. § 57-209

At least twenty days before bringing the action provided for in section 57-205 , the owner of the leased land, either by himself or by his agent or attorney, shall demand of the holder of the lease, if such demand by ordinary diligence can be made in this state, that such lease be discharged of record. Such demand may be either written or oral. When written, a letterpress carbon or written copy thereof, when shown to be such, may be used as evidence in any court with the same force and effect as the original.