If the Premises ... or any structures, improvements, fixtures and equipment, furnishings and physical property located thereon, or any part thereof, shall be damaged or destroyed by fire, the elements, the public enemy or other casualty, or by reason of any cause whatsoever and whether partial or total, the Lessee, at its sole cost and expense, and whether or not such damage or destruction is covered by insurance proceeds sufficient for the purpose, shall remove all debris resulting from such damage or destruction, and shall rebuild, restore, repair and replace the Premises ... and any structures, improvements, fixtures and equipment, furnishings and physical property located thereon substantially in accordance, to the extent feasible, prudent and commercially reasonable, with the plans and specifications, for the same as they existed prior to such damage or destruction or with the consent in writing of the Port Authority, which consent shall not be unreasonably withheld, conditioned, or delayed, make such repairs, replacements, changes or alterations as is mutually agreed to by the Port Authority and the Lessee.
Id. at § 15.1.
Source: IN RE SEPTEMBER 11TH LITIGATION