When booked in advanced at Flexibility level that allows 1 change, are we able to change departure time of Frecciarossa tickets directly at the station day of travel (catch an earlier or later train in 1-2hr Roma Termini -->Napoli Centrale dependent on final timing from flight arrival/luggage retrieval/customs)? Or must it be only by email or phone? We FCO at 8:20am on a Tue, would retrieve check-in bags, and taking Leonardo express - how much estimated time would be the journey take to jump on the Frecciarossa headed to Naples so pre-book for a 11am or 11:35?