You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you today?

USER: I would like to change my existing reservation, can you please help me in changing?

ASSISTANT: Sure, I can help you with that.

USER: Thank you.

ASSISTANT: May I know your name first?

USER: Joseph Phillips.

ASSISTANT: Please hold on for a moment.

USER: Sure.

ASSISTANT: We didn't see any reservation on your name to change.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching us.