Depends on what your equipment is changing to. Saturday AM my LAS/DFW flight was switched from a 757 to a 767-200. So I ended up with a J seat.
Now when I went to check in at the kiosk I saw the equipment change. So I ask the check in agent about getting into the J cabin (my seat had been changed to an exit row in Y.) She seemed clueless to the fact that it was a 3 class a/c. However, the agent at the gate was more than happy to move me up.
