You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Myself Brian Taylor.

ASSISTANT: How may I assist you today? Yes, Brian.

USER: Due to another plan, I would like to change my existing reservation.

ASSISTANT: Ok, let me check with your details.

USER: Sure.

ASSISTANT: Sorry to inform you Brian, there is no reservation found under your name.

USER: Ok, thank you for your information.

ASSISTANT: Can I help you with anything else?

USER: No, thank you.

ASSISTANT: Thank you for contacting us.Have a nice day.