No failure of Landlord to exercise any right or remedy consequent upon a default in any covenant, agreement, term or condition of this Lease, and no acceptance of full or partial Rent by Landlord during the continuance of any such default, shall constitute a waiver of any such default or of such covenant, agreement, term or condition. No covenant, agreement, term or condition of this Lease to be performed or complied with by either party, and no default thereof, shall be waived, altered or modified except by a written instrument executed by that party. No waiver of any default shall affect or alter this Lease, but each and every covenant, agreement, term and condition of this Lease shall continue in full force and effect with respect to any other then existing or subsequent default thereof.