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