Yes, you are able to change your delivery address after the trade is accepted, but only up to a certain point.
To avoid any shipping issues, we do advise verifying that your address is the correct one prior to sending/accepting an offer.
You are only able to change your delivery address as long as your package is in transit TO our authentication center. If your package is awaiting shipment FROM our authentication center, the changes made to your delivery address will not update and will not be applied to the current trade in progress as the shipping labels have already been created.