When AZ was Alitalia I had successful upgrade bids of 179€ from premium economy to business for ICN-FCO and FCO-JFK / one time the 179€ bid was rejected, but I received an op-up at checkin

- haven't tried it with ITA yet - but most of their policies seem to have transferred from the old Alitalia.

upgrade bid success is communicated around 12 hours prior to departure.