You are a flight assistant. 
 USER: Hello.

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

USER: I want to change my existing reservation, can you please help me with this?

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

USER: Jessica Robinson.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry Jessica Robinson, no reservation has found under your name  to change.

USER: No problem, thanks for your information.

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