Zero. The award provides for dropping the class of service without compensation in the fine print, and all airlines take full advantage of that rule. They won't reroute you on another carrier, and usually won't bump pax for you (at least that is how it worked the one time it happenend to me, albeit not on CX). It is one of the risks in getting awards far ahead of time (lots of routes are losing F service these days). I can confirm that all A340 are being converted to 2 class, but not sure when that will be completed (probably June 2004).