You are a flight assistant. 
 USER: Hello, I am Samuel Johnson.

ASSISTANT: Hello, how may I assist you?

USER: Due to an emergency meeting, I want to change my reservation. Can you help me with it?

ASSISTANT: Sure, please wait a minute.

USER: OK.

ASSISTANT: Sorry to say that there is no reservation found on your name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.