You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, may I know your good name?

USER: Sure, myself Jonathan Phillips.

ASSISTANT: I regret to inform you that there is no reservation found on your given name.

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

ASSISTANT: Thank you for opting us.