.
Go to the file (by clicking the name) and then scroll down to the Participation Info and click the button to "Set to Stop Participating"

Go to the file (by clicking the name) and then scroll down to the Participation Info and click the button to "Set to Stop Participating"

Under the Guardians Entered table, click the pencil icon next to "Set as Primary".
This will allow you to change the primary guardian.
If needed, once you have changed the Primary, you can set the other to "Stopped Participating" if that guardian will no longer be participating