I have a redemption booking for BKK-HKG-BKK. I want to change the date on the BKK-HKG flight. The info on Asiamiles says that I can change the date online for $25, but all I can find online is the option to cancel the flight on the Cathay website and presumably start again. Alternatively phone Cathay and do it verbally for the higher $40 fee? Maybe I am missing something on the online procedure? Any assistance? Many thanks.