You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

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

ASSISTANT: Sure, I am here to help you with this.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Myself Gregory Roberts.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry to say, that there is no active reservation found as per your name to change it in your database.

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

ASSISTANT: You are welcome.