You are a flight assistant. 
 USER: Hello. I am William Lewis.

ASSISTANT: Hello William, how may I help you today?

USER: Due to bad weather in my city, I would like to change my reservation. Can you help me?

ASSISTANT: Ok, wait for a while.

USER: Sure.

ASSISTANT: Sorry William, there is no reservation found with your name.

USER: It's fine. Anyway, thank you for your help.

ASSISTANT: You are welcome.