following the month in which Client provides TrueLink with a written notice of its election to terminate this Agreement. 15. ASSIGNMENT OR TRANSFER. Neither party shall assign or transfer any of its rights under this Agreement without the prior written approval of the other party, except no such approval shall be required for an assignment to a financially responsible affiliate. 16. MODIFICATIONS. This Agreement may be amended at any time and from time to time, but any amendment must be in writing and signed by the party to be charged. 17. WAIVER. No waiver of any provision of this Agreement will be valid unless it is in writing and signed by the party against whom it is sought to be enforced. No waiver at any time of any provision of this Agreement will be deemed a waiver of any other provision of this -8- 9 Agreement at that time or a waiver of that or any other provision of this Agreement at any other time. 18. UNDEFINED TERMS. Terms that are not specifically defined in this Agreement are used as set forth in the California Uniform Commercial Code. 19. POWER AND AUTHORITY. Each party represents to the other that it has all necessary power and authority to enter into and perform its obligations under this Agreement. The individuals executing this Agreement on behalf of each party represent that they have authority to do so. 20. NOTICES. All notices required or permitted to be sent under this Agreement shall be in writing and shall be sent to the parties at the addresses set forth in the preamble of this Agreement, or to such other addresses and to such other individuals of which either party may notify the other in a notice which complies with the provisions of this subsection. All notices