talk to her and ask for a training spar. If you cant beat her, go to the training room, enter the arena (doors in the middle) and click the display board in the background to select an oponent, fight to level up until you have enough health to tank her. I dont know where I got mach punch from. Possibly Inko, or its a passive you get with leveling up.
plagiarizing with his enormous "pen"
Pretending he gives a damn about our piddly-ass problems. And that's 24-7 bud.
Deplete all your ember PP's, visit the nurse, get ember PPs back through the scene with phoenix again, continue to train against the robots till the MC says they feel like they can beat Phoenix (maybe train a level or two higher for an easier fight), find her in the hallway on a weekday, interact with her again and ask for another fight/training session and defeat her. I think having the mach punch ability and being a higher level also helps
