You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I serve you?

USER: I would like to book a ticket from IAD to ATL.

ASSISTANT: Sure, may I know the travelling dates?

USER: Departure date is Oct, 13 and return by Oct, 15.

ASSISTANT: Do you have any connection limit?

USER: I would prefer direct flight.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: I am Matthew Carter.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, no flights found with your preferable dates.

USER: Thank you.

ASSISTANT: Thank you for opting us.