Cancellations: If your trip to Hawaii gets cancelled at the last moment
, or you change your reservation, you can cancel your previous reservation. This can be done online through a car rental company website on which you had made the booking. The good thing is that there are no charges for canceling your booking. Even if you accidentally happen to make two reservations instead of one, you can cancel it without any charges. The car rental company will send you an email confirming your cancellation.