You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid 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. May I know your name please?

USER: I am Stephanie Walker.

ASSISTANT: Ok, wait for a moment please.

USER: Sure.

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

USER: No problem, thank you for the information.

ASSISTANT: You are welcome.