This Agreement (including this Section 7.3 ) may not be amended except by an instrument in writing executed and delivered by the Parties. The failure of any Party at any time or times to require performance of any provision hereof shall in no manner affect the right at a later time to enforce the same. No waiver by any Party of any condition, or of any breach of any term, covenant, representation or warranty contained in this Agreement, in any one or more instances, shall be deemed to be or construed as a further or continuing waiver of any such condition or breach or a waiver of any other condition or of any breach of any other term, covenant, representation or warranty. No course of dealing between or among any Persons having any interest in this Agreement shall be deemed effective to modify, amend or discharge any part of this Agreement or any rights or obligations of any Person under or by reason of this Agreement.