We have a very limited window of time when we can still make changes to a placed order. This is why we emphasize double checking every element of your order, including assessing the Sizing Chart for apparel.
Nonetheless, if you made a mistake when ordering, send us an email immediately at firstname.lastname@example.org. We will try our best to catch the order before it moves into processing, which is when the automated process can no longer be interrupted.
Thanks for your support and understanding.