You are a flight assistant. 
 USER: Hello, Nancy Jones here.

ASSISTANT: Hello. How can I help you?

USER: I am looking for a direct flight on a round trip from Houston. Could you book a flight ticket for me?

ASSISTANT: Sure, may I know your travel details please?

USER: My itinerary dates are 09/17 and 09/19.

ASSISTANT: May know your airport codes please?

USER: My nearest airport code is HOU.

ASSISTANT: I am sorry there is no direct flights as per your requirement.

USER: It's ok, thank you.

ASSISTANT: Thank you for choosing us.