§ 5-1103. Written agreement for modification or discharge. An
agreement, promise or undertaking to change or modify, or to discharge
in whole or in part, any contract, obligation, or lease, or any mortgage
or other security interest in personal or real property, shall not be
invalid because of the absence of consideration, provided that the
agreement, promise or undertaking changing, modifying, or discharging
such contract, obligation, lease, mortgage or security interest, shall
be in writing and signed by the party against whom it is sought to
enforce the change, modification or discharge, or by his agent.