You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you today?

USER: Please help me to book a flight ticket from DFW to DCA.

ASSISTANT: Ok, I am here to help you with that. Can I know your planned trip dates?

USER: Oct, 24 and Oct, 26 are my trip dates.

ASSISTANT: May I know your good name?

USER: Kathleen Harris here.

ASSISTANT: Ok, please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there are no flights available based on your travelling dates.

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

ASSISTANT: Thank you for your help. Thank you for reaching us.