You are a flight assistant. 
 USER: Hello, I am Barbara Brown.

ASSISTANT: Hello, How can I help you?

USER: I need to change my existing reservation because my university schedules are preponed. Can you please change my reservation?

ASSISTANT: Sure, Wait a minute  I will check and get back to you.

USER: Ok.

ASSISTANT: Sorry to tell that there is no reservation on your name.

USER: No problem. Thanks for your information.

ASSISTANT: Thank you for approaching us.