In most cases it is not possible to add to or change the order once it is placed. Our fast turnaround of orders means that orders are sent for packing at our warehouse soon after being placed and it becomes very complicated to change. If you do need to change the order, then we suggest contacting us as soon as possible.
If you want to add to the order, then we usually suggest placing a separate order for those additional items and noting in the comments to combine the orders and refund the extra shipping fee. Note that in some cases where the additional items have moved the combined size to the next shipping bracket, we may not be able to refund the extra shipping cost.