Disable f4 key for Launchpad
It's not that F4 is set as Launchpad, it's that you have your F-Keys set as 'special function' keys &amp; that special function happens to be Launchpad. (The set of little squares printed on the key next to F4 - each of those icons represent the special functions)

If you look at the first tab of that pref pane - Keyboard - You'll see that box is unchecked…

Once you do that, your 'real' F-Key will come into play, with whatever you set it for in the Shortcuts pane.
Alternatively, you can temporarily swap special function/F-Keys by holding  Fn