Civic's securely encrypted backup allows you to retain access to your identity if you delete and reinstall Civic app and even across devices. Your Civic backup is stored locally on your device. To remove your Civic ID, first, delete your Civic backup, then, uninstall the Civic app.
If you are an iPhone user, please see instructions here for deleting backup on iCloud.
If you are an Android user, please see instructions here for deleting backup on Google Drive.
*Warning: removing backup will remove access to all previously authorized partner services.