You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Debra White here.

ASSISTANT: How can I help you?

USER: I want to attend a Seminar in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, can I have your nearest airport codes please?

USER: My airport codes are from DTW to DCA.

ASSISTANT: May I know your planned travel dates please?

USER: My travelling dates are from 09/25 to 09/27.

ASSISTANT: Please wait a moment.

USER: Ok, I will wait.

ASSISTANT: White, no flights has been found on your journey dates.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for approaching us.