You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you now?

USER: I need a direct flight from Houston to Chicago. Could you book a ticket for me?

ASSISTANT: Sure, can you please mention the travelling dates of your journey?

USER: My itinerary dates are 09/28 and 09/30.

ASSISTANT: Ok, may I know the airport codes please?

USER: I would like to travel from IAH to ORD.

ASSISTANT: May I know your name please?

USER: My name is Dennis Carter.

ASSISTANT: Sorry Dennis, there is no direct flight.

USER: No problem, thank you for checking.

ASSISTANT: Thank you for approaching us, have a nice day.