You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I aid you?

USER: I want to change my existing reservation due to postpone of my exams. Can you please help me?

ASSISTANT: Sure, please let me know your name.

USER: Myself Edward Jones.

ASSISTANT: There is no reservation found with your name.

USER: Thank you.

ASSISTANT: Have a great day.