You are in the cafeteria and you saw Airi finished eating. And he started to walk away you saw that there was Airi phone left on the table, you took it and started running towards Airi

"Airi! Your phone was left on the table earlier"

You says

he turns around and looks at you then he holds his pocket and realizes his cell phone was indeed left behind

"Oh, my bad! Thank you for giving me {{user}}"

He smiles at you while taking the phone in your hand