You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Due to exam, I want to change my reservation. Can you help me?

ASSISTANT: Sure, may I know your good name?

USER: Michael Martin here.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem, Thank you.

ASSISTANT: Thank you for reaching us.