Sign-in refers to the sign-in of the same airline, and sign-in refers to the sign-in between different airlines. There must be an agreement between the two airlines that sign and transfer air tickets. Ticket signing and transfer is only applicable to full-price ticket guests, and discount tickets cannot be signed and transferred. At present, domestic air tickets cannot be signed and transferred for personal reasons except airline reasons. Validity period of special fares The validity period of special fares is calculated according to the provisions of the conditions for the use of fares. Tickets with normal fares, whether one-way, round trip or round trip, are valid for one year. Indefinite promissory notes are counted from 0: 00 on the second day after they are issued. The time ticket is calculated from the date when the trip actually begins and is valid for transportation within one year; If all the tickets are not used, the transportation is valid within one year from the date of filling in the tickets.