A person can be removed from a group by going to each group and removing them individually but that can take a lot of time when they’re part of multiple groups. You can easily remove multiple groups from a person at once using the People screen.
When a person is removed from a group, they will no longer have access to the group, but the messages and history will still be available to everyone else.
Step 1. If necessary, make sure you're in the Manage Organization area.
Step 2. Click the People panel option to display all the people in the organization.
Step 3. If necessary, you can search or filter and select the specific person you are looking for.
Step 4. Hover over the group you want to remove the person from, and click the Remove from Group option (to complete the process and remove the user from that group.)
Remove from Group option.
Step 5. Repeat step 4 to remove the user from as many groups as needed.