Dude, you committed the greatest sin in air travel these days.....you assumed (and we all know what happens when you do that). If you have a corporate travel agency, they should have advised that it was a time sensitive fare and if you bought it online, you should have checked the fare rules. These time sensitive fares have saved me and my company a ton of money but I always know when I can switch and when I can't. I never take it for granted that they will let me standby for another flight - especially on one of these type of fares.