You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to change my existing reservation. Could you help me?

ASSISTANT: Sure, can I have your name to check with the previous reservation?

USER: Cynthia Scott.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no active reservations on your name to change.

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

ASSISTANT: Thank you for reaching our service.