Yes. You can upgrade your car before you start your trip by clicking the link on your rental voucher.
All modifications depend on what is available at the time. If you change your booking in any way it is likely that the price will change. Depending on the change you wish to make, we may have to cancel one car and book another one.
Sometimes, the counter staff will offer you an upgrade when you go to pick up your car. If you decide to upgrade at the counter, you will pay the car hire company directly.