You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you for the day?

USER: Can you please change my existing reservation as my plan to meet my friend got postponed?

ASSISTANT: Sure, I am gleeful to help you with that. May I know your name please?

USER: I am Benjamin Roberts.

ASSISTANT: Please wait for a while. Thank you for waiting.

USER: Sure.

ASSISTANT: There is no reservation found on your name in our database to change it.

USER: Ok, no problem. Thank you for the information.

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