It is true that Flex fares (both economy and business) do not have a so-called penalty fee, i.e. a fee that is charged each time a change is made to a ticket. What does this mean? If the same fare (same price offer, same fare conditions) is available on the new selected date, the change can be made at no cost.
However, if the fare is currently higher, we will need to pay a surcharge on top of the price of the new ticket.
The amount of the surcharge depends on the availability of the selected booking class and will be indicated during the rebooking process.