You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I want to change an existing reservation, so please help me in changing the reservation.

ASSISTANT: Sure, I will help you with that. Can I have your good name please to check your reservation status?

USER: Myself Jeffrey Johnson.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

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

USER: Not an issue. Thank you.

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