As you may very well be aware, you may right-click on an indicators' settings and save them as default, so every time you load that indicator, your specific settings state will persist. But what if you want to change them back?
It's actually very simple; you just delete the template file created. Each time you save as default, it actually creates a template file, which you can remove. The templates can be found in the following location:
The NinjaTrader7 folder is found under "My Documents"
The files will be named as the indicator. Just find the indicator that you want to revert to it's original state and delete the .xml file.