An order change can change quantity, variants, or timing. Its practicability depends on the state of the preparation and the actual arrangements. At organisational level, it is necessary to avoid that the request is received from one part of the process and ignored by those who have to produce or deliver.
I propose to distinguish received request and confirmed change. As long as the verification is not completed, the initial order and variation proposal must remain recognizable. Informal communication may be insufficient if it involves multiple people and documents already used for the job.
In a hypothetical example, a retailer asks to change the size distribution. Modification may be possible for some variants and not others. A precise answer makes it possible to understand what will be delivered, without attributing to silence a meaning of confirmation.
The final check must use a shared version of the order. The quality of the relationship also depends on the possibility of reconstructing what has been agreed upon. A well-managed variation makes the effects clear and reduces the correction work after the products are shipped.