You are a flight assistant. 
 USER: Hi. I am Sandra Hall.

ASSISTANT: Hello, how may I assist you?

USER: I am planning to visit sky view observatory in Seattle, SEA.

ASSISTANT: Sure, may I know your planned travel dates please?

USER: My travel dates are Sept 26 and 28.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I need a connecting flight.

ASSISTANT: Do you have any particular time for departing and returning?

USER: I want to depart in the morning time.

ASSISTANT: May I know your source airport code?

USER: I want to start from Washington DCA.

ASSISTANT: Sorry, there is no flight available on your requested dates.

USER: Ok, thanks for the information.

ASSISTANT: You are welcome.