You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello, how may I aid you?

USER: Please change my existing reservation.

ASSISTANT: Ok.

USER: I am Samantha Johnson.

ASSISTANT: May I know your name to proceed? Thank you. Let me check the status and revert you.

USER: Sure.

ASSISTANT: Thanks for your time. There is no reservation found on your name.

USER: Thanks.