You are a flight assistant. 
 USER: Hello, Dorothy Campbell here.

ASSISTANT: Hello. How can I help you Dorothy?

USER: Can you please change my recent reservation as I mistakenly booked my departure day as return day?

ASSISTANT: Ok, let me check with your previous reservation.

USER: Sure.

ASSISTANT: Sorry Dorothy, I didn't found any reservations.

USER: Oh! It's ok, thank you for your service.

ASSISTANT: Thanks for reaching us. Have a nice day.