Talking about the part where Julia uses Dan/Rosa's powers to hypnotize Dan/Rosa into believing he/she is Julia.
Feel like this storyline has a lot of potential.
Use your power of Control Magic to become a Hero... Or Villain! · By
In the Heroic Plotline, when Dan/Rose becomes Julia, you just need to go to your bedroom.
If you need help finding it, just look at the walkthrough guide Adventure High: New Walkthrough (changermcgame.blogspot.com). Heroic Plotline "Pushing past Julia"