English to Czech Bus/Financial Law (general) stock rotation right

Side letter refers to any agreement or correspondence between a XXX representative and a customer, supplier or partner, which modifies or amends any of the terms and conditions specified in the original contract, agreement or purchase order and are prepared outside or apart from an Operating Unit’s standard process and procedures for contract/order amendment, which must include sending it immediately to the Operating Unit’s accounting and financial control organization. (This includes but is not limited to clauses to offer programs such as stock rotation rights or rights of return.)