It is not possible to change the payment method and number of installment months for an already purchased ticket (Card>Accounting Transfer or A Card>B Card is not available.).
All tickets purchased prior to boarding are required to be refunded and a new ticket should be issued. A refund fee will be charged according to the fare regulations.
For more information, please contact your place of purchase or the Jin Air Customer Service Center (1600-6200).
Also, it is not possible to change the payment method upon completion of the boarding.