I'm on a 6am flight but need to delay departure as much as possible due to work (ideally get on 9pm flight). Can I call at 5am to switch to the 8am, then again at 7am to the 10am, all the way down to the 9pm? I would really not prefer to pay the change fee since i'm not sure that I will even be able to make it out at all! There is loads of availability tomorrow on all the flights (which I know could change, but it's a risk that I will take). Anyone know?