You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Lisa Carter, I had a reservation to San Francisco for vacation but due to some problem my vacation is postponed. Can you change my reservation?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: Ok, thank you for the details.

ASSISTANT: Thank you for opting us.