You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I need to book a ticket from OAK to IAD. Could you book a ticket?

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

USER: Travel dates are May, 31 and June, 2.

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

USER: I prefer connecting flight.

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

USER: I would like to depart in the morning time.

ASSISTANT: Do you have any class preference?

USER: I am comfortable with any class preference.

ASSISTANT: Do you have any airline preference?

USER: I prefer to fly in a normal-cost airlines.

ASSISTANT: May I know your good name please?

USER: My name is Brian Johnson.

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

USER: Thank you.

ASSISTANT: Thank you for reaching us.