You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you now?

USER: I want to change my reservation, can you help me with that?

ASSISTANT: Sure, I will help you with that.

USER: Thank you.

ASSISTANT: Can I know your name to check your previous reservation?

USER: James Turner here.

ASSISTANT: Please be on hold to check.

USER: Sure.

ASSISTANT: We regret to inform you that, there is no reservation found on your name in our records.

USER: Ok, thank you.

ASSISTANT: Thank you for contacting us, have a great day.