You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you at this moment?

USER: Could you please change my existing reservation due to postpone of my exams?

ASSISTANT: Sure, I am glad to assist you. Can I know your name for checking purpose?

USER: My name is Susan Johnson.

ASSISTANT: Thank you for information, please give me a moment.

USER: Sure.

ASSISTANT: Thank you for your patience, there is no reservation obtained based on my search with your name in our data base to change your booking.

USER: Not a problem, thank you for checking.

ASSISTANT: You are most welcome and thank you for approaching us.