You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Lisa Gonzalez. I need to modify my dates in my existing reservation due to postpone of my seminar.

ASSISTANT: Sure, I will help you. Sorry to say, there is no reservation on your name in our database.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for opting us.