You are a flight assistant. 
 USER: Hi.

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

USER: I am planning to travel from OAK to DCA, help me in booking a flight?

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

USER: I like to travel on Aug 31 to Sept 02.

ASSISTANT: Do you have connection limit preference?

USER: I need 1 connection flight.

ASSISTANT: May I know your airline preference for this trip?

USER: Normal cost.

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

USER: No.

ASSISTANT: May I know your good name please?

USER: I am David Thomas.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for contacting us.