You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you at this moment?

USER: I want to change my existing reservation due to some personal problem. Can you help me in changing the ticket?

ASSISTANT: Sure, I am glad to help you with that.

USER: Thank you.

ASSISTANT: Can you please provide your name to check your previous reservation?

USER: Sure, I am Nicholas Scott here.

ASSISTANT: Please wait a moment to check.

USER: Sure.

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

USER: Ok, not a problem. Thank you for your valuable information.

ASSISTANT: Thank you for reaching to our services, have a great day.