retain (something) over (someone or something)
To hold onto or continue to have control, power, influence, etc., over someone, something, or some group. I'm stepping away from the day-to-day business of the company, but I still retain control over any major decisions. I know Sarah's mother retains a lot of influence over her, even though they live in different parts of the country.
retain something over someone or something
to keep or maintain something, such as power or control, over someone or something. Tony found a way to retain control over Fred. I wish to retain veto power over the committee.