How do I "forget" an out-of-range Wi-Fi network on a Galaxy S7?

I want to remove old saved networks that are no longer in range. I can forget visible networks, but out-of-range networks are not visible anywhere so I can't do the standard long-tap => "Forget Network" action.

There is no option for "Saved Networks" or "Manage Networks" under the built-in Wi-Fi app's "More" menu.

I have tried a third-party app, WiFi Manager, where the networks are visible but reported an error on forget:

Android 6 allows apps to change (edit password, forget) only those networks that were originally "created" in same app.

I quite distinctly remember being able to view saved networks on previous Android phones...

My phone is rooted, so methods requiring root are acceptable, but it's better if that's not necessary.

I have an Australian (CSC XSA) Galaxy S7 Edge (SM-G935F).

Apparently this was a problem with the S6, where the 'solution' was to use third-party Wi-Fi management apps that no longer work in Marshmallow.

• http://forum.xda-developers.com/galaxy-s6-edge/help/how-forget-range-wi-fi-networks-t3137257


• http://forums.androidcentral.com/samsung-galaxy-s6/596840-how-do-i-forget-saved-wifi-networks-when-they-out-range-samsung-devices.html


• http://forums.androidcentral.com/samsung-galaxy-s6/567924-how-do-i-remove-saved-wifi-other-locations-my-samsung-galaxy-s6.html


• http://ericscorner.blogspot.com.au/2016/02/how-to-remove-out-of-range-wifi.html

But that no longer works, as per the error message above...