You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Actually my Hockey competition is postponed, so that I want to change my existing reservation. Can you help me?

ASSISTANT: Please may I know your name?

USER: Ok, I am Shirley Perez.

ASSISTANT: May I know your desired travel dates please?

USER: Ok, my planned trip dates are on Aug 12 and return on Aug 14.

ASSISTANT: Can I know your preferred airport codes please?

USER: Ok, my airport codes are from ORD to DFW.

ASSISTANT: Do you have any specifications?

USER: I need a direct flight to travel.

ASSISTANT: Sorry to say, there is no flight on your desired travel dates.

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

ASSISTANT: Thank you for opting us.