You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: As my exam got postponed, I want to change my existing reservation. Can you help me out?

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

USER: Sure, my name is Robert Martinez.

ASSISTANT: Please wait for a moment.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: You are welcome always.