You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation due to my exams are postponed. Can you help me for that one?

ASSISTANT: Sure, I am here to help you with this. May I know your good name please?

USER: Sure,Ronald Evans here.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

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

USER: No issues, thank you for the information.

ASSISTANT: You are welcome.