You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: Due to heavy storms in Chicago, I would like to change my existing reservation to Chicago.

ASSISTANT: Sure, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: On which name your previous reservation has been booked.

USER: Previously, I have reserved my ticket with the name of Shirley Evans.

ASSISTANT: Ok, wait a moment.

USER: Sure.

ASSISTANT: Sorry Evans. There is no reservation found on your name to change.

USER: Ok, may be my friend has already changed my reservation on behalf of me.

ASSISTANT: Ok.

USER: Thank you for your information.

ASSISTANT: Welcome. Thank you for approaching us.