You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. May I know your name Please?

USER: I am Margaret Lopez.

ASSISTANT: Nice to meet you Lopez. How may I assist you today?

USER: I had done flight ticket booking last week to spend my holiday vacation with my family. But, due to some weather conditions I would like to change my booking which I have done. Can you help me out of it?

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: Sorry Lopez, I cannot find any reservation with your name.

USER: Ok, thank you.