You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: Can you please assist me to change my existing reservation?

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

USER: Thank you.

ASSISTANT: Can I have your good name please to check your reservation status?

USER: I am Thomas Lopez.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Thomas Lopez, no reservation has found under your name to change.

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

ASSISTANT: Thank you for choosing us, have a good day.