You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Betty Hill.

ASSISTANT: Hello Betty, how can I help you?

USER: One of my friend has invited me to attend a VIVA Awards event in Chicago.Can you book a flight ticket for me?

ASSISTANT: Sure, can I know your places of travel?

USER: My preferable dates are 01/18 and 01/20.

ASSISTANT: Can I know on which day you want to fly?

USER: My airport codes are DTW and ORD.

ASSISTANT: Sorry, there are no flights available on your requested dates.

USER: That's ok. Thank you for your information.

ASSISTANT: Welcome.