You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,. How may I assist you ?

USER: Due to sudden changes in weather conditions, I want to change my existing reservation. Can you help me with that?

ASSISTANT: May I know your name ?

USER: My name is Emma Brown.

ASSISTANT: I am sorry there is no reservation.

USER: Ok, Thanks for the information.

ASSISTANT: Thanks.