You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how best I can help you today?

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

ASSISTANT: Sure, we are here to help you. May I know your name please?

USER: My name is Donald Hall.

ASSISTANT: Ok, please be on hold.

USER: Sure.

ASSISTANT: Sorry we could not find any reservation with your name in our database.

USER: Thank you.

ASSISTANT: Thank you for opting us.