You can simply change the target layout of the script. You can create two or more layouts with the exact same name. This can cause problems if you do this based on a name calculation. This is why FM uses the internal layout number. It is also nice when you decide to change a layout name but still want everything to work, which is usually the case for most people.
The other option would be to create a duplicate and name that one OLD while you make changes to the working layout.
I would say that changing the layout target for the one navigation script is the better way. This is usually what I do.
Thanks for the fast responses!
All of these are helpful options.
Maybe I am going about buttons the wrong way (specifically for buttons navigating throughout my solution)
There are actually many layouts that have this same button... so I'm sensing that instead of using "Specify Layout" on the individual the Button Setup, any time I have buttons that appear on many Layouts, I should use "Perform Script" and do the redirecting there so that I have a more global approach to making changes.