Log into your account, pull up the itinerary, and look for something like "request upgrade" to click. If this does not work, call DL at your new Silver number or not, enter your DL FF number, and ask to be added to the upgrade list. It is best to do this as early as possible so that you can check on the computer that it was done right. If this does not seem to work, try removing and re-entering your FF number, or ask a phone agent to do this, but this is not supposed to be necessary any more.

If the flight is very empty in FC, Silver upgrades should clear at about 5-6 pm in ATL TWO days before the flight or you might get a gate upgrade.