The Buddy Project

Kiya ignores KD's phone calls and remains grimfor forgetting her birthday. When Piddi tells Anirudh about Kiya and KD's problem, he agrees to help them. However, KD scolds Piddi for involving Anirudh. Later, KD succeeds in impressing Kiya and she forgives him. What did KD do that made Kiya forgive him?