The Parties may, by written agreement, (a) extend the time for the performance of any of the obligations or other acts of the Parties, (b) waive compliance with, or modify, any of the covenants or conditions contained in this Agreement, and (c) waive or modify performance of any of the obligations of any of the Parties; provided that no such waiver or failure to insist upon strict compliance with such obligation, covenant, agreement or condition shall operate as a waiver of, or an estoppel with respect to, any subsequent insistence upon such strict compliance other than with respect to the matter so waived or modified.