If the ticket was purchased online from MOBY, it is possible to change it directly in your personal area, provided you are a registered member of the MOBYCARD programme. The fare difference can be paid by credit card (also with a rechargeable or prepaid card), Visa, Visa Electron, Mastercard, Maestro, American Express and Diners Club.
Once the change has been made, the new ticket will be sent to the e-mail address provided at the time of booking.