change (someone's) mind
To convince someone to think differently about something. You can try all you want, but you're not changing my mind about going to that party! I need to change my teacher's mind about me. I swear I'm not a slacker, but that's what she thinks!
change someone's mind
to cause a person to think differently (about someone or something). Tom thought Mary was unkind, but an evening out with her changed his mind. I can change my mind if you convince me that you are right.
change (one's) mind
To reverse a previously held opinion or an earlier decision.