How to Change FluentProvider Theme from Child Component?

[tgram-3D]

This seems like a very basic question but I'm having trouble finding any documentation on this. If I want to have a button or something in a child component to switch themes, how do I do that? I figured the useFluent hook can be used to get the current provider instance but I don't know how to properly set the theme.

 <FluentProvider theme={teamsLightTheme}>
            <Root />
   </FluentProvider>

So if I want to change the theme to teamsDark or something without drilling props through Root, how do I do that?