You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I aid  you today?

USER: I am Scott Davis. Please change my existing reservation.

ASSISTANT: Sure, we are glad to serve you. Please hold a moment, let me check your reservation with us and let you know.

USER: Ok.

ASSISTANT: Thanks for your valuable time, sorry, unfortunately no reservation found with the provided name.

USER: Thanks.

ASSISTANT: Thank you for reaching us, have a great day ahead.