Once successfully rebooked, you can either pay less at pick-up or get refunded after your trip. For fully prepaid bookings, the difference will be refunded to the same card you used to pay, and it may take 7-15 working days to process. For partially prepaid bookings, the prepay price difference will be refunded to the same card you used to pay, and it may take 7-15 working days to process. For pick-up bookings, you just pay less at pick-up.