(1) An agreement modifying a lease contract needs no consideration to be binding.
(2) A signed lease agreement that excludes modification or rescission except by a signed writing may not be otherwise modified or rescinded, but, except as between merchants, such a requirement on a form supplied by a merchant must be signed separately by the other party.
(3) Although an attempt at modification or rescission does not satisfy the requirements of sub. (2), it may operate as a waiver.
(4) A party who has made a waiver affecting an executory portion of a lease contract may retract the waiver by reasonable notification received by the other party that strict performance shall be required of any term waived, unless the retraction would UCC - LEASES 411.2145 be unjust in view of a material change of position in reliance on the waiver.