So I am taking flight 1429 from JFK all the way to ANC with a stopover in SLC. When I booked the flight, I didn't bother to check to see if either segment (between JFK-SLC or SLC-ANC) was available for upgrade; I only looked at the flight as a whole 1429 from JFK - ANC. I was waitlisted for the JFK - ANC, but then later checked and found that there were upgrades available from JFK - SLC. I called to see if I could use my points or certificates to upgrade that segment of my travel and Delta told me no. Because it is the same flight number, the upgrade needs to be available the entire way through. This is the most ridiculous thing that I've ever heard. So I'm waitlisted for the upgrade, and say all of a sudden an upgrade opens up from SLC - ANC, I won't be able to be upgrade that segment either unless there is also still an upgrade available from JFK - SLC.
Thanks for all of the platinum benefits Delta!