You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Owing for an emergency, I want to change my reservation. Can you please do that for me?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your name to check the reservation list?

USER: Sure, my name is Alexander Walker.

ASSISTANT: Sorry  Alexander Walker, there is no reservation on your name.

USER: No problem. Anyway, thank you for checking.

ASSISTANT: Thank you.