I faxed DL a short letter about my circumstances (moving to SEA, not well-served by UA for one route I'll be taking frequently) along with a copy of my 1K card and a current account statement, and I requested a match to Gold or higher.

I sent the fax in the late evening of Tuesday, July 20 and currently see (very late evening of Wednesday, July 21 / very early morning of Thursday, July 22) "Gold Medallion | Sky Priority™" in my profile at delta.com. Good deal!