You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. What can I do for you?

USER: I am looking for a direct flight, could you please help me with booking a direct flight from IAD?

ASSISTANT: sure, I will help you with that. May I know your details for finding a flight?

USER: I would like to take off on 03/25 and return on 03/27.

ASSISTANT: May I know your destination airport codes please?

USER: My destination airport code is PHL.

ASSISTANT: May I know your name for documentation purpose.

USER: I am Elizabeth Parker.

ASSISTANT: I am sorry no flights available  on your request.

USER: That's ok, I will find an another alternate way to complete my trip.

ASSISTANT: Thank you for choosing us.

USER: Thank you for the help.