I'm from the USA, I did call back and the second rep told me with confidence that a reshipment is not the case at all. They just sent over a notice to the shipping department, and if they can upgrade it they will, and if not they will ship it out with normal shipping. She clarified that the rerouting/reshipping business is for people who want to change the shipping address or if they want to add an additional item to their order, but that doesn't happen if I simply want to upgrade the shipping service. She DID say that the upgrade was not guaranteed, but confirmed again that if I don't receive overnight shipping, it will just go through automatically as regular shipping.