Requires landlords to mitigate damages when commercial tenants vacate premises in violation of the terms of the lease

S 421 requires commercial landlords to make reasonable efforts to re-rent vacated premises when tenants leave early in violation of lease terms. Landlords must try to rent the space at fair market value or the original lease rate (whichever is lower), and the new lease would replace the previous tenant's obligation. Any lease clause attempting to exempt landlords from this duty is void under the bill. This directly affects commercial landlords and tenants in lease disputes, shifting the responsibility to minimize financial harm to landlords who fail to actively seek new tenants.