You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: My plans to visit Washington Entrepreneur summit has been postponed, I would like to change my existing reservation.

ASSISTANT: May I know your name?

USER: My name is Mary Carter.

ASSISTANT: Sorry, there is no reservation found.

USER: Ok, no issues.

ASSISTANT: Thank you.

USER: Thank you for your help.