If you no longer want to use your device to authenticate using PingID, you'll need to unpair it.
Access the My Devices page. The My Devices page opens, showing the devices you currently have paired with your account. The primary device is shown in green.
Select the device, or authentication type that you want to remove. You may be asked to authenticate using your primary (default) device.
Click the icon to the right of the device you want to remove to expand the entry, and then click the trash icon. You'll now be prompted to confirm your request.
If you only have one device or authentication method paired with your account, next time you log on you will be prompted to register a device in order to access your account.