You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Actually, I have done my flight ticket reservation last week.But, due some weather change I would like to change my reservation. Can you help me out of it?

ASSISTANT: Yes, I am here to help you. May I know your good name please?

USER: I am William Miller.

ASSISTANT: William Miller, wait a moment please.

USER: Ok.

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

USER: Ok. Thank you for the information.

ASSISTANT: Thank you for reaching us.