You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

USER: I am Barbara Brown. Owing to an emergency, I want to change an existing reservation. So please help me in changing the reservation.

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, we couldn't find any reservation on your name.

USER: Not an issue. Thank you.

ASSISTANT: Thank you for availing us.