Question for other JFK based flyers. If I'm flying a JFK-FLL-SJO trip as the outbound leg of a RT, when I'm checking in at the Mosaic desk, is it possible to get the EMS upgrade for the FLL-SJO leg from the desk at JFK? Seems like it'd be the easier place to try as opposed to waiting until FLL if I'm going to get the 2nd boarding pass at the time.

Thanks!