I bought eZed's on SWA and when I tried to change the dates on them I ended up having to refund them and buy new ones. It may have been specific to SWA, but I eventually found a note on the MyIDtravel web site that said that you couldn't change the tickets. The good news is that the refund happened within a couple of days, so it's not a big deal.

Looks like most majors are on board with MyIDtravel. Alaska is an exception. It's nice to not have to bother with a Delta ticket counter anymore.