You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I want to book a connecting flight from SEA to DCA. Can you please help me with the booking?

ASSISTANT: Sure, I am here to help you. Can you please provide your journey dates?

USER: Sure, I want to travel on Sept 19 and need to return on Sept 21.

ASSISTANT: Do you have any class preference for this trip?

USER: Yes, I prefer an economy class for this trip.

ASSISTANT: Do you have any other specifications for this trip?

USER: No.

ASSISTANT: May I know your good name please?

USER: Myself Joseph Gonzalez.

ASSISTANT: Joseph Gonzalez, there are no flight services are available on this route on your provided dates.

USER: Ok, no problem. Thank you for the information.

ASSISTANT: Thank you for contacting us.