You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am planning to change an existing reservation, due to bad weather condition. Can you please change my reservation?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: I am Donna Thomas.

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

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

ASSISTANT: Thank you for opting us.