So glad I came across this thread today. Just five minutes ago, noticed that both the T and K fare for a ticket had dropped significantly in price for me and a companion. Well below my original booking price. Plus U space had opened.
I was able to GARR online, but it forced me into the T-fare online. The website wanted to charge a change fee for my companion to upfare, but I was able to call in to upfare to the K-fare (for $10 each) with no change fees and apply a Gold Guest cert. Woohoo! Saved some money PLUS got an upgrade.
Thanks to ANC for asking the question, and EskimoGirl for answering.