Samsung Galaxy Note9
Android 8.1
1 Find "Fixed dialling numbers"
Press Phone.
Press the menu icon.
Press Settings.
Press More settings.
Press Fixed dialling numbers.
2 Turn on fixed dialling
Press Enable FDN.
Key in your PIN2 and press OK.
3 Turn off fixed dialling
Press Disable FDN.
Key in your PIN2 and press OK.
4 Return to the home screen
Press the Home key to return to the home screen.