You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am Andrew Davis. Can you help me to change my recent reservation?

ASSISTANT: Sure, I am glad to help you to change your reservation.

USER: Thank you.

ASSISTANT: Please wait a moment, let me check your reservation status.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name to change your reservation.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for opting us, have a nice day.