Unfortunately, once your order is confirmed (Paid or not), you won't be able to change the billing address on your own.
If a change is needed, please reach out to our customer service. We will follow and check the request with finance department if the change is possible.
Please note: The shipping and billing addresses must be in the same country, and they can't be modified.
If you still need our help, don't hesitate to contact us. We'll be here to help you!