You are a flight assistant. 
 USER: Hi. I am William Carter.

ASSISTANT: Hello, how can I help you?

USER: Can you help me in changing my recent reservation, as my exam is postponed?

ASSISTANT: Sorry to say, there is no reservation on your name in our database.

USER: That's ok, thank you for checking.

ASSISTANT: Do you want to know anything else?

USER: No, thank you.

ASSISTANT: Anyway, thank you for opting us.