This Agreement may only be amended or modified by an instrument in writing signed by each of the parties hereto.  No failure or delay on the part of either party to this Agreement in the exercise of any power or right, and no course of dealing between the parties hereto, shall operate as a waiver of such power or right, nor shall any single or partial exercise of any power or right preclude any further or other exercise thereof or the exercise of any other power or right.  Any waiver of any provision of this Agreement, and any consent to any departure by either party from the terms of any provision hereof, shall be effective only in the specific instance and for the specific purpose for which given.  Nothing contained in this Agreement and no action or waiver by any party hereto shall be construed to permit any violation of any other provision of this Agreement or any other document or operate as a waiver by such party of any of his or its rights under any other provision of this Agreement or any other document.