From the Windows desktop, navigate: Start 
> Settings icon 
> Network & Internet
Tap or click Wi-Fi, then tap or click Manage known networks.
Tap or click the appropriate Wi-Fi network name.
Tap or click Forget.
From the Windows desktop, navigate: Start > Settings icon > Network & Internet
Tap or click Wi-Fi, then tap or click Manage known networks.
Tap or click the appropriate Wi-Fi network name.
Tap or click Forget.