Excellent customer service from Delta
I booked an economy seat on Delta.com for a codeshare flight on Virgin Atlantic SFO to LHR. I wanted to purchase an upgraded seat but was unable to do this on Virgin Atlantic's site. I contacted Delta and was routed to their ticket reissue department. The agent Sarah spent about 20 minutes working her way through the bureaucracy to allow me to purchase an Economy Delight seat and then went to the VA web site and selected the seat I wanted. I have no special status on either airline, so I was extremely pleased with her excellent service. (I have no experience with VA's Economy Delight, so I hope the seat is worth it.)