You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: As my business meeting has postponed, I want to change my existing reservation.Can you help me out?

ASSISTANT: Sure, can I know your name please?

USER: Yes, my name is Matthew Rodriguez.

ASSISTANT: Please wait for a moment.

USER: OK.

ASSISTANT: I am sorry Matthew, I didn't find any recent reservation with your details.

USER: OK, thank you.

ASSISTANT: You are welcome.