You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER:  As I am a scientist, I want to attend science festival with my students at Washington. Can you do the reservation?

ASSISTANT: May I know on what dates would you like to travel?

USER: My journey dates are 03/27 and 03/29.

ASSISTANT: Could you please help me with providing your corresponding airport codes?

USER: My airport codes are PHL-DCA.

ASSISTANT: Do you prefer any layover in between journey?

USER: I need only direct flight.

ASSISTANT: Do you require any specifications in your journey?

USER: Return time should be evening.

ASSISTANT: Sorry to inform you that unfortunately there is no flights available by the given details.

USER: No issue, Thanks for the information.

ASSISTANT: May I know your name?

USER: Patricia Johnson here.

ASSISTANT: Thank you.