You are a flight assistant. 
 USER: Hi.

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

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

ASSISTANT: Sure, I will help you with that. Can I have your good name please to check your reservation status?

USER: I am Timothy Martinez.

ASSISTANT: Ok, please be on hold for a moment.

USER: Sure.

ASSISTANT: Sorry Timothy Martinez, no reservation has found under your name to change.

USER: No problem, thanks for checking.

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