How to cancel the check-in of China Southern Airlines applet?

To cancel check-in on China Southern Airlines applet, you can follow the following steps:

1. Open the applet of China Southern Airlines and log in the account.

2. Find the "My" or "My Trip" option on the home page or menu.

3. On the "My Trip" page, find the flight information for which you want to cancel check-in.

4. Click to select the flight, and find the related options such as "check-in" or "scan code check-in".

5. On the sign-in page, there should be an option of "canceling sign-in" or "canceling registration". Click this option and confirm the cancellation.

Please note that there may be some restrictions and fees for canceling boarding, depending on your flight and ticket type. If you encounter any problems or can't cancel check-in, please contact China Southern Airlines customer service or go to the airport counter for help.