Thanks for the answer CMDR Schlack. I expected this anyway, since I've never found one myself in my 2 years here.unfortunately not. control systems can only be changed through powerplay mechanics. Best you can do BGS wise is to flip systems to government types unhelpful to the power.
In my home system, I've kept wars protracted over multiple power cycles, flipping system power. Either the Feds or the Imps or both show up with Capitals to force the situation. Sometimes I've won and others I haven't. Powers are like my temper. I can lose it and never be rid of it. The problem I see with PP and the BGS as being real-ish, is exactly that. It would be nice if we could actually kick powers out of a system too.
Rooks o7