You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,.

USER: I am Brian Taylor.

ASSISTANT: How may I assist you?

USER: I want to change my existing reservation due to medical emergency. Can you help me?

ASSISTANT: Sure, I will help you out.

USER: Thank you.

ASSISTANT: Please standby.

USER: Sure.

ASSISTANT: Thank you for being patience.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found in your name.

USER: Thanks for your quick response.

ASSISTANT: Thank you for opting us.