Just to follow up - I ended up calling after midnight at over the phone for a $25 fee they got me on:

FL 196 LAS-JFK 21:20-05:12
FL 155 JFK-MCO 06:55-09:43

instead. I could have stood-by on that flight for no fee accord' to them, but I didn't want to deal with the hassle and instead have seats on the better flight.

Very easy! Nice work JB.