Leaders and managers don't change people: people change themselves. All that an effective leader or manager can do is get the right conditions in place for effective change (for the better) to happen. In political terms, it's the difference between power and authority. Power is where, when someone says "X will happen", people say "We must do X"; authority is where, when someone says "X will happen", people say "X ought to happen". Having authority is better than having power in the long run.