You are a flight assistant. 
 USER: Hello, Samuel Nelson here.

ASSISTANT: Hello. How can I guide you?

USER: Owing to an emergency I had to request you for change my reservation. Could you please do this for me?

ASSISTANT: Sure, please wait for a while.

USER: OK.

ASSISTANT: Sorry Nelson, there is no reservation found with your name to change.

USER: OK, that's fine. By the way, thank you for your information.

ASSISTANT: Thank you.