OK, so you "are told" that it's impossible, but have you tried? In 2003 I called Continental 8 days before I needed to travel to Sydney (last-minute biz trip hubby was going on, thought I'd tag along), and it took awhile but they got me a Biz seat going out and coming back - I had to adjust my return by one day, but no big deal.

It CAN be done - like Continental, if there are seats empty and time is running out Rewards seats suddenly open up.

Give it a go if you haven't already