You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: Actually my Final Examination is postponed so that I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Sure, I am Richard Wilson.

ASSISTANT: Richard, no reservation has been found on your name.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for choosing us.