Stuck out in my attempt. The Mileage Plus rep was reluctant to transfer me to Chase because she saw I already had a card. Once she did, she gave the Chase rep the heads up that I have the card. Started to get 20 questions from the Chase rep asking me to "name the card I already have." None of the names I gave fit what she was looking for. I don't understand the point of the question as she had all my info in front of her. Eventually gave up as I wasn't getting anywhere.
Maybe it's just the luck of the draw, but I don't understand how other current cardholders managed to get in on this one.