If GVIDO is already registered in My Library, you must first delete the device information remaining in the account as follows.
Log in to your My Library on your PC.
Enter " Register/Manage device" at the top of the screen
The “Device List” screen will appear. Click “︙ (3-point reader)” at the right end of the registered device name, and select “Delete” from the dialog box that appears.
Click “Delete” in the “listed device” dialog to delete the device registration .
Now All you have to do can be done through "Settings": resetting your typed history, initializing the device to factory default, or obtaining the instructions manual.