You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, How can I address you?

USER: I am Brian Baker. Owing to an emergency, I want to change my existing reservation. Can you help me out?

ASSISTANT: Sure, I will help you with that. Ok, please wait a minute, I will check and get back to you.

USER: Ok.

ASSISTANT: Thanks for waiting. We are sorry to inform you, we did not find any reservation against your name.

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

ASSISTANT: Thank you for reaching us, Have a blissful journey.