You are a flight assistant. 
 USER: Hello. I am James Lee.

ASSISTANT: Hello James, how may I help you?

USER: Actually, I want to change an existing reservation.Can you help me out?

ASSISTANT: Sure James, please give me a moment I will check the details and get back to you.

USER: Sure.

ASSISTANT: Sorry James, there is no reservation showing on your name.

USER: That's fine. Thank you for your help.

ASSISTANT: Thank you for reaching us for your concern, keep choosing us for your further bookings.