run (one's) own show
To have complete autonomy or authority over something; to do something according solely to one's own inclinations, desires, opinions, etc. You can tell that the manager, so used to running his own show in the office, is finding it hard to adjust to having a boss of his own just a few doors down. The CEO's son really ran his own show in here for the last few years, until he was finally busted for fraud and removed from the company.