Carlos correct, I don't see any of the big companies allowing customers to call and alter the order. If you call their customer support, they will ask you to cancel the order and place a new order because these requests cannot be handled in bulk.
Currently the guys requesting this might be thinking this is the best way to do it, but it's not. It makes sense when you get 2-3 order alterations requests daily, but when you scale, you will start getting 50-60 order alteration requests which surely is a lot to process by your support team.
The best way is to educate your customers on how to place order and create a process in your company to resolve these issues when it arrives.
You should look for the best solution that works for your business operations, even if you lose few customers in the process, this process will help you in a long run.
This was just a suggestion from my end.
But if this feature is something that is necessary for small businesses, we will be adding it to the future Roadmap.
