Originally Posted by GagaPilot

New policy is that agents are no longer allowed to re-issue the ticket when an RUC/GUC clears until T-24 before departure. This means that if there are any schedule changes the UG is subject to having to re-clear if there is no inventory available at the time. It's an extremely customer unfriendly policy that allows your UG to be lost and gives DL a chance to sell the F seat. You can occasionally get an old-school agent who will reissue because they understand just how bad of a policy this is. But most newer agents simply won't do it because they are supposedly risking discipline for doing so.

So now the best odds for using an RUC/GUC is to find availability around 1-2 months prior to departure when schedule changes aren't as likely. Any further out and the schedule changes will occur. Any closer in and availability isn't likely there.

YMMV.