>>58627561Yancy, a celebrity.
if you interact with any TV you'll see her shows, where she uses the name Nancy.
At Nimbasa you'll find her lost xtransceiver, which she asks you to keep for a while because she's too busy to pick it up.
From then on she'll start calling you at certain specific tiles in many routes and cities. Initially she asks you about yourself, but later she starts telling you about her life.
You eventually give her the Xtransceiver back (while she's using her real name and trying her hardest to keep the fact taht she's famous a secret). You can call her many times after that (this is a little convoluted because the game picks one of the 15 specific tiles where she called you initially and you can only call her from that tile, and the tile changes every time you call her), this gives you many cute interactions like her blushing or accidentally calling you while she's at work and quickly hanging when she realizes she's calling you as Nancy instead of Yancy.
Once you're close enough she'll trade you a bunch of pokémon with their hidden abilities