This Agreement may not be released, discharged, abandoned, changed or modified in any manner, except by an instrument in writing signed on behalf of each of the parties to this Agreement by their duly authorized representatives. The failure of either party to enforce at any time any of the provisions of this Agreement shall in no way be construed to be a waiver of any such provision, nor in any way to affect the validity of this Agreement or any part of it or the right of either party after any such failure to enforce each and every such provision. No waiver of any breach of this Agreement shall be held to be a waiver of any other or subsequent breach.