This Agreement may be amended, modified, superseded, canceled, renewed or extended and the terms or covenants hereof may be waived, only by a written instrument executed by all of the parties hereto, or in the case of a waiver, by the party waiving compliance.  The failure of either 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 either party of the breach of any term or covenant contained in this Agreement, whether by conduct or otherwise, in any one or more instances, shall be deemed to be, or construed as, a further or continuing waiver of any such breach, or a waiver or the breach or any other term or covenant contained in this Agreement.