Open a run box window (or press win+R) then type cmd to open Windows 8 CLI.
To see stored wireless profiles, type:
   netsh wlan show profiles
This will show a list of saved profiles of your connected WLAN devices. Then you'll need to write/save/memorize the profile name that you want to change.
To see the stored key (WPA/WEP/etc) of a specific profile:
   netsh wlan show profiles name=[profile name] key=clear
You'll find the key content under security settings.
To delete a stored profile:
   netsh wlan delete profile name=[profile name]
This will delete the stored profile of every WLAN interface. If you want to delete the profile of a specific WLAN interface, you need to use the following:
   netsh wlan delete profile name=[profile name] interface=[interface name]