You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I want to book a flight ticket to visit Houston Zoo with my children at HOU, can you help me with booking a connecting flight?

ASSISTANT: Sure, on which dates do you want to book your tickets?

USER: My trip dates are Nov 12 and Nov 14.

ASSISTANT: May I know your source point?

USER: My source point is IAD.

ASSISTANT: Do you have any airline preference?

USER: Yes, I want to fly in normal-cost airline.

ASSISTANT: Can I know your flight timing?

USER: My depart time is afternoon.

ASSISTANT: May I know your name?

USER: I am Kevin Baker.

ASSISTANT: Sorry, there are no flights available.

USER: Ok, no problem.

ASSISTANT: Thank you for choosing us.

USER: Thank you.