I was told on the phone I couldn't change my regular ressie to get a Ding fare. It had to be a new reservation. When I went to the screen to try and change it, the Ding fare wasn't offered only the internet fare.
What I did on my last trip since I had $59 fares and wanted the $49 ding fares was get on the phone with a rep and had them cancel and I made the new Ding fares with the old confirmation # (so I wouldn't have to pay and use the same dollars). He cancelled and I placed. He said that sometimes if I had cancelled online, it might take a minute, an hour or a day for that money to be available again but calling made it immediately available. Plus I wanted the same flights I had originally scheduled. A little gymnastics but I have an $80 credit which I used last night to book $43 fares BWI to FL in late Sept. Now I'm holding my breath for a good Ding to come home the 2nd week of October.
Or maybe I'll be stuck in FL!!!