You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you?

USER: Please change my existing reservation.

ASSISTANT: Ok, may I know your good name please?

USER: I'm Jessica Scott.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, no reservation found with your name.

USER: Thanks for the help.

ASSISTANT: Thank you for choosing us.