With the Flexi fare is that you can change train when you want, even at the last minute!

Paying 20% more than the Standard fare rate, you can enjoy the maximum flexibility in the use of your ticket.

The trains allowed under the Flexi fare are the Eurostar AV, T-Biz, Eurostar, Eurostar City Italia, Intercity Plus, Couchettes, Wagon Lits and Excelsior carriages.

To sum up:

Trains allowed	Trains with simultaneous seat reservation: AV, T-Biz, ES*, IC Plus, Couchettes, Wagons-Lits, Excelsior
Reductions allowed	Ragazzi; Cartaviaggio Executive
Change reservation	Before the train leaves: twice free After it has left: once, within 24 hours, with no extra charge
Change ticket	Once free until the the booked train's departure
Get another train	This is allowed on the same day and until 24 hours after the train you have booked leaves without penalty, but subject to any differences in the rate for the other train
Refund	Before the train leaves: refund less 20% After it has left, within 24 hours refund less 50% or a voucher for 80% of the fare. The request may only be made at the place of departure or issue, provided that the place of issue and the destination are not the same. No replacement vouchers may be issued