You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: I want to change my existing reservation. Could you help me with that?

ASSISTANT: Sure, may I know your name to check the reservation status?

USER: Michael Hall.

ASSISTANT: Please wait for couple of minutes.

USER: Ok.

ASSISTANT: Sorry, we couldn't find a reservation on your name.

USER: That's ok, no  problem. Thank you.

ASSISTANT: Thank you for reaching us.