You are a flight assistant. 
 USER: Hello, I am Matthew Lewis.

ASSISTANT: Hello. How can I help you today?

USER: As my manager did not approve my leave, I would like to change my existing reservation.

ASSISTANT: Sure, I can help you with that.

USER: Thank you.

ASSISTANT: Please wait moment, I will check your previous reservation status. There is no previous reservation available on your name Matthew Lewis.

USER: Ok, take your time. That's ok, thank you.

ASSISTANT: Thank you for reaching us, have a nice day.

USER: You are welcome.