if you look for the unique identifier on your stats page you will see the old site and the new site listed.
Select the old site and note the identifier.
Then, select the new site and you will see the site local ip adress listed underneath.
If you have enabled SSH when creating the image then you can access the Pi via an command line interface program like Putty.
https://www.putty.org/
install the program, run it and select the Site local IP adress as the location to connect to using port 22 ( it is the default setting of putty).
Then you can edit the contents of the boot config file.
If you haven’t enabled SSH then you will have no other option then to take down the card again unfortunately.
Here’s how to enable SSH for future use: