You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Brandon Martinez. I want to change my existing reservation, can you please help me with this?

ASSISTANT: Sure, I am here to help you with this intent. Sorry Martinez, there is no reservation on your name to modify any reservation.

USER: Ok, no problem. Thank you for your time.

ASSISTANT: You are welcome always.