You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I would like to change my existing reservation, can you help me in that?

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

USER: Sure, myself Jerry Wright.

ASSISTANT: Please allow me a moment.

USER: Sure, take your time.

ASSISTANT: There is no reservation found under your name in our data base.

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

ASSISTANT: Thank you for contacting us.