You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: Could you please help me to book a flight ticket to travel from OAK to IAH?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: I want to travel on Jan 20th and 22nd.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I don't have any depart time preference but I do want to return back in the afternoon.

ASSISTANT: Would you like to travel in a direct flight or a connecting flight?

USER: I can not spend my time in travelling so please look for a direct flight.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: No problem, thank you.

ASSISTANT: May I know your good name please?

USER: My name is Dorothy Young.

ASSISTANT: Thank you.