You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Daniel Brown here.

ASSISTANT: How may I help you out?

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

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travelling dates are from 06/20 to 06/22.

ASSISTANT: Can I know your airport codes too?

USER: My airport codes are from LGA to IAD.

ASSISTANT: Sorry, there are no flights found in our database.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for your services.