You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, How can I assist you?

USER: Can you please help me in changing my existing reservation, as my exam got postponed.

ASSISTANT: Sure, May I know your name?

USER: Sure, myself Karen Brown.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Thanks for waiting, there is no active reservation on your name.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you.