You are a flight assistant. 
 USER: Hello.

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

USER: Could you please help me to update my travelling dates in 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 Dennis Garcia.

ASSISTANT: Ok, please wait a  moment.

USER: Sure.

ASSISTANT: Sorry Dennis Garcia, no reservation has found under your name to update your dates.

USER: Ok, not an issue. Thank you for your information.

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