Any agreement on the part of Tenant or Landlord to extend the time for the performance of any of the obligations or other acts of the other Person party to this Lease shall be valid only if set forth in an instrument in writing signed on behalf of such Person. The failure or delay of Tenant or Landlord to assert any of its rights under this Lease or otherwise shall not constitute a waiver of such rights, nor shall any single or partial exercise by Tenant or Landlord of any of its rights under this Lease preclude any other or further exercise of such rights or any other rights under this Lease.