I filled in the wrong passport number when I booked the plane ticket. The agent said it had been revised for me. How to confirm that it has been modified?

You can call the customer service who booked the ticket and ask him to check whether it has really changed. If it has been changed, it is better. If you haven't changed it, you can ask customer service to help you change it.

If the passport number is wrong, there are two situations. One is that there is no ticket, and the other is that there is a ticket. If there is no ticket, before the plane takes off, call the website that bought the ticket for you or the airline that issued the ticket, and follow the voice prompts to find the customer service department. They can help you modify your passport number in the system, which is absolutely possible. If you find it incorrect when boarding, you may not be able to board the plane. If a ticket is issued, it doesn't matter. General boarding process: border inspection-security inspection-boarding gate. Just look at your passport, visa and boarding pass with your name on it at the border checkpoint. After passing the security check, the airline staff will get the boarding pass twice, and you can go.