You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I would like to change my reservation as my exams postponed, can you please help me out with that?

ASSISTANT: Please let me know your name?

USER: Thank you. Myself Jonathan Brown.

ASSISTANT: Sorry, there is no reservation by your name.

USER: Ok, no problem. Anyway thank you for checking out.

ASSISTANT: Thank you.