Hey Joe

I've hardly ever had luck with last minute request, but as for contacting them by phone, do it before 10am (HK time) or after 4pm - I've found that the telephones are pretty jammed up in the middle of the day.

The problem with the online request is that you don't get the AM / MPC people offering you alternatives. If it's not too late, give it another shot and try call first thing in the morning. I've found that they are mostly really helpful (and very apologetic if they can't accomodate your request).

Cheers
AT