You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how can I help you?

USER: I am Justin Smith.

ASSISTANT: Ok.

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

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your name.

USER: Thanks for your help.

ASSISTANT: Thank you for opting us.