S1·E24 Chii Wears And Takes Off

Hideki takes Chii to work. There, Chii changes into the wrong uniform. Ueda tells her it's the wrong one, but before she goes to change, Yumi sees her wearing it from outside the shop and runs away crying. As it turns out, Yumi used to work at the store, and that had been her uniform. When Yumi was working for Mr. Ueda, the two had started falling in love, but when Yumi learned about Mr. Ueda's previous marriage to a Persocom, she concluded that he believed Persocoms to be superior to humans, so she quit her job at his bakery and broke off the relationship.