You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I assist you now?

USER: Can you please change my reservation?

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

USER: Ok.

ASSISTANT: Please let me know your good name to check your reservation status.

USER: I am Melissa Green.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Melissa Green, no reservation has found under your name to change.

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

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