Effective Date of this Modification

Effective Date of this Modification. The date upon which this Modification shall become effective, which shall occur upon close of escrow in accordance with all conditions of the certain Escrow Instructions agreed upon by the Parties respecting the Offer to Purchase Real Estate and Acceptance — Air Force Plant 70 or 29 November 1998, whichever is later. However, should close of escrow occur after 29 November 1998, this Modification shall apply to costs incurred after 29 November 1998 as otherwise provided for in this Modification.