The furnishing of the form of this Lease shall not constitute an offer. This Lease shall become binding on Landlord and Tenant only upon its execution by and delivery to each party. Further, this Lease is subject to approval by any Mortgagee or Ground Lessee of Landlord. If Landlord can obtain said approval only upon the basis of modifications of the terms and provisions of this Lease, Landlord shall have the right to cancel this Lease if Tenant refuses to approve in writing any such modification within fifteen (15) days after Landlord's request therefor. If such right to cancel is exercised, this Lease shall thereafter be null and void, and any Security Deposit or Advanced Rent Payment made to Landlord shall be returned to Tenant and neither party shall have any liability to the other by reason of such cancellation.