RedBaron
Some Trenitalia-Tickets are exchangeable:
BASE: without restriction and free of charge
ECONOMY: by paying the difference between ECONOMY and BASE.
Online exchanges are possible when you buy tickets through Trenitalia or some other resellers, but not SBB. You have to call the Contact Center. When you make an online exchange after importing the ticket in Trenitalia app, the original reseller (e.g. Rail Europe) is not informed about this exchange. Therefore the ticket becomes “technically” non-refundable, although it may still be refundable according to the tariff.