You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, what can I do for you today?

USER: I want to change my exiting reservation, due to bad weather conditions. Can you help me to change it?

ASSISTANT: Sure, I am glad to help you.

USER: Thank you.

ASSISTANT: May I know your name to trace the details?

USER: Sure, Please check my reservation on the name of Carol Williams.

ASSISTANT: Ok, please wait for a few minutes.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name to change.

USER: Ok, thanks for your service.

ASSISTANT: Thank you for availing us.