You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,.

USER: My name is Raymond Thompson.

ASSISTANT: May I assist you ?

USER: I want to change my existing reservation due to an emergency.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: I am sorry, no reservation exists by name Raymond Thompson.

USER: No problem, thanks for giving information.

ASSISTANT: Have a nice day!.