You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am David Thompson.

ASSISTANT: How may I aid you today?

USER: I am planning to change my reservation to another destination, so can you help me to change my reservation?

ASSISTANT: Sure, I will help you with that.

USER: Ok.

ASSISTANT: Please wait for a minute to check your previous reservation.

USER: Sure.

ASSISTANT: There is no reservation found on your name in our records.

USER: That's ok, thank you.

ASSISTANT: Thank you for contacting us, have a great day.