Extremely belated follow up here, but does that mean their abilities don't effect fire that's already there? Or does it just mean that fire that's already there won't like, disappear from where it's at and reappear in the character's hand?

For example, I've been having Raju's moods effect fire that's already in fireplaces, like making it act differently, making it grow, etc, as well as him being able to conjure his own. Can characters manipulate natural fire too? If so, are there limits to what they can do with it?