You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: Can you help me to book a flight ticket from DFW to IAD?

ASSISTANT: Sure, can you please share your travel dates?

USER: Mar, 25 and Mar, 27 are my travel dates.

ASSISTANT: May I know your connection limit?

USER: I would prefer single connection.

ASSISTANT: Do you have any other specification that you are looking for?

USER: No, thanks.

ASSISTANT: May I know your name to proceed further?

USER: Catherine Lee here.

ASSISTANT: I am sorry to inform you that there is no flight available at your request.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for contacting us.