Asked for what seemed to be an overbooked in biz SIN-HKG flight a couple of weeks back. The check-in agent was overjoyed, but a quick call to whoever told that things had been sorted.

Noted a manifest at the gate with something along the lines 'Pls seek 2 JCL pax for voluntary downgrade with SGD 632 cash compensation' at the bottom of the page.

Be vocal and ask- likely it won't be confirmed till the last minute.