You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Can you help me to change my existing reservation?

ASSISTANT: Sure, I'll help you in changing an existing reservation.

USER: Thank you.

ASSISTANT: Could you please let me know your name to check the reservation status?

USER: Please check the under name of Brian Evans.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Thank you for waiting, sorry to inform you that there is no reservation found by this name.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for approaching us.