You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello,. How can I aid you?

USER: I would like to change my existing reservation.

ASSISTANT: Ok. May I know your name please?

USER: My name is Carol Thompson.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: Thanks for the help.

ASSISTANT: Thanks for reaching us.