What should I do if the itinerary cannot be printed for more than 28 days?

In this case, you can only contact the ticket office and ask them to give you a special tax invoice.

The itinerary is the "Air Transport Electronic Ticket Itinerary" which is supervised by the State Administration of Taxation and is included in the invoice management of the tax authorities. The ticket itinerary is officially online and is the payment and reimbursement voucher for passengers purchasing domestic air transport electronic tickets. .

For the itinerary, it is not only a special invoice, but also a transportation voucher, and it is also the preliminary evidence and registered securities (tickets) for the establishment of the air transportation contract.