Unsupervise an iPhone, iPad, or Apple TV in Apple Configurator
Unsupervising an iPhone, iPad, or Apple TV erases all content and settings on the device, including apps and media. If you want to preserve the data on a supervised device, make a backup of it first. Supervised device backups are handled in two different ways:
When restored to the original device, that device is still supervised.
When restored to any other device, that device is unsupervised but available for supervision.
You can unsupervise a device by erasing all content and settings. See Erase a device.