How do I search for Y-Up fares?
I've recently started traveling for work(only domestic flights at the moment) and many times, I have been able to purchase a coach ticket with an instant upgrade to First/Business Class. My work generally lets me pick which flight I want but only lets me fly coach so this instant upgrade is always nice. My question is, how do I know before booking whether it is a ticket with an instant upgrade or not? The agent I spoke to said this was a Y-Up fare - how do I search for Y-up fares?
My work uses American Express for corporate travel, if that makes a difference.