You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I am Ronald Nelson. Can you help me in changing my recent reservation, as my exam is postponed?

ASSISTANT: Please wait a while.

USER: Sure.

ASSISTANT: Sorry to say, there is no reservation on your desired travel dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.