The issuance of information, advice, approvals or instructions by Buyer's technical personnel or other representatives shall not be deemed requests for, or approvals of, a change to this Agreement and shall not affect Buyer's and Seller's rights and obligations hereunder unless the same is in writing, signed by the BAPR and expressly states that it constitutes a change to this Agreement in accordance with this Clause. All changes or modifications to this Agreement shall not become effective until duly signed by the BAPR.