I ordered 4 shirts last night on the $9 sale. My sister just emailed me and told me that the size I ordered for her is wrong, she forgot about American Apparel running small.

My order status says my order is still open for changes, but I'd have to cancel and place a new order to do so. If I do that, can I still get yesterday's sale prices? I just need to change a size on one of them. I don't want to lose the good deal on the other three.