The following article explains how to delete the Plunge All-In from the Plunge app. 

Reasons you might need to do this:

• Troubleshooting connectivity issues
• Changing the WiFi network
• Transferring ownership to someone else

On the "My Products" screen, tap the three dots and expand the menu and select "device settings"
Once in device settings, scroll down to the bottom and tap "Delete the device"
If connected, the device will restart and put itself in pairing mode again before deleting it from the app.   If NOT connected, the device will be deleted from the app.