You give her the device, before you tell her than she can use it for only three times, then she has to give it to you.
She accepts, you know you can believe her so you let her do what she wants.
So for her first "transformation" she wants to experiment the device. She sees two men who every time they see her start to hit on her heavily. Every time she refuses, every time she explains that she will never go out with them even if they become the sexiest men or womans of the world. Olivia saw thats two men look at her and start to walk in your direction.
When they was close enough she merges them with another poor girl next to them. Olivia made the personality of the girl dominant and starts the process.
Again, you and only Olivia remember the existence of the two dredgers and the young woman. Now they are one only woman, come here to flirt with the first man she sees.
She spotted a gorgeous man and goes talk with him.
She already have her second idea.