You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

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

ASSISTANT: May I know your name for the changing process?

USER: Sure, Mark Davis here.

ASSISTANT: Thank you, please wait for a minute. Sorry, we couldn't find a reservation on your name to change.

USER: Ok, no issues. Thank you for your information.

ASSISTANT: Welcome, thank you for reaching us.