system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
"""
report recording the correct number of pages; or 20.2.3 send the Notice by recorded delivery or registered post and retain a receipt of delivery or sending; or 20.2.4 send the Notice by registered airmail if it is to be served by post outside the country from which it is sent and retain a receipt of sending. 20.3 The details of the Parties for the purpose of Notices are as follows: 16 Each Party may alter the above details that relate to it and shall promptly notify the other of any such change by a Notice in accordance with this Clause. 20.4 Any Notice shall be deemed to have been served: 20.4.1 if delivered by hand, at the time and date of delivery; 20.4.2 if sent by fax, at the time and date of the successful fax transmission report; 20.4.3 if sent by recorded delivery or registered post, 48 hours from the date of posting (such date as evidenced by postal receipt etc); or 20.4.4 if sent by registered airmail, five days from the date of posting. 21 GENERAL 21.1 Variations only in writing 21.2 No variation of or amendment to this Agreement (including its Schedules) shall be effective unless made in writing and signed by or on behalf of both Parties or by their duly authorised representatives. 21.3 Remedies cumulative 21.4 The rights, powers and remedies provided in this Agreement are (except as expressly provided) cumulative and not exclusive of any rights, powers and remedies provided by law, or otherwise. 17 SHBV For the attention of: Managing Director Address: With copy to: Managing Director, Telephone number: Fax number: W2E For the attention of: Mr John Murphy Address: Dargavel Stores, Lockerbie Road, Dumfries, DG1 3PG Telephone number: [Insert details] Fax number: [Insert details] 21.5 No partnership or agency 21.5.1 Nothing in this Agreement shall (except as expressly provided) be deemed to constitute a partnership, or create a relationship of principal and agent for any purpose between the Parties. 21.5.2 Any statement or representation made by either Party shall not be binding on the other unless agreed otherwise agreed in writing and neither Party shall be liable to any third party for any loss or damages arising out of such statements or representations. 21.6 No waiver 21.7 The failure to exercise, or delay in exercising, a right, power or remedy provided by this Agreement or by law shall not constitute a waiver of that right, power or remedy. If a Party waives a breach of any provision of this Agreement this shall not operate as a waiver of a subsequent breach of that provision, or as a waiver of a breach of any other provision. 21.8 Costs of each of the Parties 21.9 Each Party shall bear its own costs and expenses in connection with the preparation, negotiation, and execution of the Agreement. 21.10 Third Party Rights A person who is not a party to this Agreement may not enforce any of its provisions under the Contracts (Rights of Third Parties) Act 1999. 21.11 Counterparts / Execution of Agreement 21.12 This Agreement may be entered into by the Parties in any number of counterparts. Each counterpart shall, when executed and delivered, be regarded as an original, and all the counterparts shall together constitute one and the same instrument. This Agreement shall not take effect until it has been executed by both the Parties. This Agreement may be validly exchanged and delivered by fax. 21.13 Severability 21.13.1 If any Clause, or part of a Clause, of this Agreement, is found by any court or administrative body of competent jurisdiction to be illegal, invalid or unenforceable, and the provision in question is not of a fundamental nature to the Agreement as a whole, the legality, validity or enforceability of the remainder of this Agreement (including the remainder of the Clause or sub Clause which contains the relevant provision) shall not be affected. 21.13.2 If the foregoing applies, the Parties shall use all reasonable endeavours to agree within a reasonable time upon any lawful and reasonable variations to the 18 Agreement which may be necessary in order to achieve, to the greatest extent possible, the same effect as would have been achieved by the Clause, or the part of the Clause, in question. 22 GOVERNING LAW 22.1 This Agreement is governed by English law. 22.2 The Parties submit to the non-exclusive jurisdiction of the courts of England and Wales. This Agreement shall come into force on the date given at the beginning of this Agreement.
"""

Extract the exact clause related to "Agreement Date" from the excerpt above.