You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I would like to change my existing reservation, can you please assist me in changing?

ASSISTANT: Sure, may I know your name please?

USER: Michelle Green.

ASSISTANT: Wait a while, kindly.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found for the user name in our data base to change your previous booking.

USER: Ok, no issues. Thank you.

ASSISTANT: Thank you for opting us.