You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I best serve you today?

USER: Owing to an emergency, I need to change my existing reservation.

ASSISTANT: Ok. May I know your good name please?

USER: I am Joshua Carter.

ASSISTANT: Thanks for providing your name, no reservation found with your name.

USER: Thanks for the assistance.

ASSISTANT: Thanks for opting us.