It depends on the type of train ticket or fare you bought. While rail passes are issued in the name of specific passengers and must match that traveler's passport, regular e-tickets or train tickets as of now are not associated with specific passengers and conductors do not require ID on the train. For most tickets, names are not required to appear in the ticket as of now, therefore you do not need to change your e-ticket if you entered the wrong name in the reservation by mistake. Please note that we have received notification that this can change soon, and the tickets will be nominative. The passenger, though is required to be properly identified at all times when travelling.
There are exceptions to this rule, however.
If you purchase a ticket on an overnight train or a cross-border train, those tickets are for individual passengers and conductors do require ID, passport and or valid documentation to enter into a new country like VISA or the appropiate entry documentation. If you entered the wrong name you might need to change your reservation and rebook your trip. In case you purchased a restrictive fare, you might lose it as super-economy fares which are the most restriuctive, do not allow changes. We recomend you to always buy a fare that allows at least 1 change like the Economy fare.