Save and delete entries based on checkmarks

I’m creating a Checkin / Classroom register app. I’ve created a Type called Checkin which lists my users. My checkmark saves a new Checkin with the user name.

How do I reverse this? How can I remove a Checkin entry if I uncheck the box in the repeat group?

The screenshot shows my repeat group and checkmarks on the left with just a print out of all Checkin entries on the right.

How I would do it, not knowing much about your app environment:

Checkbox could be a single icon that is an empty checkbox style by default – add conditions based on the state of the current cell in the repeating group: WHEN this cell’s Checkins contains Current User THEN this icon = checkbox with check

Workflows:

WHEN this icon is clicked AND WHEN this cell’s Checkins contains current user THEN make changes to a thing -> remove Current User from list

WHEN this icon is clicked AND WHEN this cell’s Checkins DOES NOT contain current user THEN make changes to a thing -> add Current User to list