Yes, you can. The flow depends on your device.
In the flight feed, you need to cancel the check-in.
Then click on the word "Canceled".
Go through all the screens to the passenger screen. Click on the passenger you want to edit.
Edit the information and click Done / Next. Then submit the check-in again.
You can cancel your check-in in the flight feed.
Select the passenger you want to edit.
Correct the information and save it by clicking the "Next" button. Submit your check-in request.