I have a direct report who, from Day 1, has clearly been resentful of being junior to me. I can't be certain why but my best guess is, because she's very ambitious, she is resentful that someone the same age as her is two job titles above. She did NOT apply for my job and started around the same time as me, so there's no clear reason for her to feel entitled to be 'equal' to me in the hierarchy.
I thought I had figured out a way to manage her. For the last few months I've had no hint of attitude or resentment when giving her tasks. Yesterday I found out that's because she's been working on other senior managers in the department and trying to maneuver herself into a more sideways position to me, even trying to get herself a new line manager. I have spoken to those senior managers and put a stop to it.
I'm now thinking of ways to reinforce the team hierarchy - making it clear I'm in charge of the team - without outright sitting her down 1:1 and laying down the law. With her personality, that will not go well and has to be my last resort.
Any advice on how this could be done?