You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I need to change my existing reservation as my exams got postponed, Can you please help me with that?

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

USER: Thank you.

ASSISTANT: May I know your name please?

USER: Thomas Anderson here.

ASSISTANT: Please wait for a mean while.

USER: Sure.

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

USER: Ok, no problem. Thanks for your information.

ASSISTANT: You are welcome.