take someone aside
to remove someone temporarily from the group for the purposes of discussing something privately. I'm sorry he insulted you. I'll take him aside and talk to him about it. I took aside my secretary and explained the procedure.
Also, take to one side. Talk to another privately or away from others, as in The doctor took Pat aside to explain what she had to do, or The boss took William to one side rather than criticize his work in front of his colleagues.
To take someone away from a group in order to speak privately: The teacher took me aside and told me not to tease the other students. The principal took aside the troublemakers who were causing problems.