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

ASSISTANT: Hello, how may I aid you?

USER: I want to change my existing reservation due to bad weather condition, can you please help me with that?

ASSISTANT: Sure, please wait a minute.

USER: Ok.

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

USER: Not an issue, thank you.

ASSISTANT: Thank you for reaching us.