MSPGUY
I was trying to do the same thing as you when I saw your post. I have had no luck finding exactly how to do it on the Delta website either. Seems like it should be pretty simple. They tell you how many miles it will take but not how to go about doing it.

I just want an upgrade to first class on my return flight using my skymiles.
PDX to DTW, coach Q class, on 4-11-10