How do I delete a device ?
Is this what you are looking for?
How do I remove a device from the Devices section?
First, make sure that the device is not currently connected to your home network. Select the name of the device either from the Devices section or from the profile where the device is assigned. Select Device Details, and then Forget Device. This will remove the device from the Devices section and unassign it from the profile that it was associated with (if applicable). It will also permanently delete all historical network activity for this device. If the device reconnects to your home network, it will appear as a new device.