You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I would like to visit Dallas, could you please book my flight ticket from IAD to DFW?

ASSISTANT: May I know your dates on which you are planning to depart and arrive?

USER: Thank you. I have to depart on June 4th and return back in the evening on June 6th.

ASSISTANT: Are you comfortable with connecting flight or direct flight?

USER: I prefer for a connecting flight.

ASSISTANT: Please let me know if you have any other specifications, I'll search for the flights according to that.

USER: I don't have any other specifications.

ASSISTANT:  If you can help me with your name, I can check with the availability of flights.

USER: Myself Anna Robinson.

ASSISTANT: Sorry, no flights are available in this route as per your requested dates.

USER: Sad to hear that. Thank you for the information.

ASSISTANT: Thank you for reaching us.