It was a nightmare for us. First few days before departure we went to the some approved office to cancel it and they said that you don't have to worry about it. So we went to the airport on departure date without cancelling it and they said that we have to cancel it before we can leave. We had a very short time left for the plane take off. Worst day ever. Ran from place to place to cancel it within a short time. Amount to cancel it was DH500. Luckily we had the money with us. Phew!