If you have a volunteer who is no longer serving, you can mark their profile under the Engagement tab in People. Doing this will stop them from receiving background check reminder e-mails and will remove them from your list of people still needing a background check.
From the member's profile in People select the Engagement tab.
Next, Select the blue "Edit answers" button.
Select "True" from the "Is No Longer Serving" drop down.
Scroll Down and select the blue "Save" button