For reserved AREX express train tickets, even after completing airline baggage check-in at Seoul Station, you can generally 'change the departure time.' However, you need to go to the ticket counter in person to change your ticket, and it's subject to seat availability on your desired train. The usual policy is: the first change is free; from the second change onward, a fee of 1,000 KRW is charged per change, up to a maximum of three changes. If you made your reservation online, you can also request a time change online, following the same rules. If the original departure time has already passed, changes are usually not allowed, and you’ll need to either request a refund or buy a new ticket at the station, depending on local regulations.

Excuse me, if I’ve already reserved a seat on the AREX and checked my luggage at Seoul Station, can I still change to an earlier departure time?