You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to book a ticket from IAD to DEN, can you help me?

ASSISTANT: Sure, can I know your travelling dates?

USER: My travel dates are Jan 20 and 22.

ASSISTANT: On which name should I reserve the flight ticket?

USER: Book the ticket in the name of Joseph White.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: Which class do you prefer?

USER: I have provided all my requirements.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: Sorry, there are no flights found on given dates.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.