You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you now?

USER: I am Jeffrey Miller. I want to change my reservation.

ASSISTANT: Ok Jeffrey Miller, I will help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Sure.

ASSISTANT: Sorry Jeffrey Miller, no reservation has found under your name to change.

USER: That's ok.

ASSISTANT: Thank you for choosing us, have a good day.

USER: Thank you.