I contacted @Delta from the air yesterday when I noticed on the app that arrival into SEA was delayed and I'd been protected on a later flight SEA-SFO. Seats were under gate control, but @Delta assigned a seat for me, and later also was able to put me back on my original flight in case we made up time in the air (the system had automatically removed me from it).
Didn't get the Porsche transfer
but did make the original connection ^