You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, provide the airport codes.

USER: My airport codes are EWR-DCA.

ASSISTANT: May I have the travel dates?

USER: My journey dates are 07/26 and 07/28.

ASSISTANT: Is there any connection limit?

USER: I need only direct flight.

ASSISTANT: Is there any class preference?

USER: I am comfortable with economy class.

ASSISTANT: Are there any more preferences?

USER: No.

ASSISTANT: May I know your name please?

USER: Samantha Hill here.

ASSISTANT: Give me a moment.

USER: Ok.

ASSISTANT: Samantha Hill, I regret to inform that there are no flights on your route with the given dates.

USER: No problem, Thanks for the information.

ASSISTANT: Thank you for reaching us.