You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Melissa Green. I want to book a ticket from DCA to SEA, can you help me?

ASSISTANT: Sure, can I know your travelling dates?

USER: My travel dates are 03/31 and 04/02.

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: My depart time is in the afternoon.

ASSISTANT: Which class do you prefer?

USER: I have provided all my requirements, I am comfortable with any flight.

ASSISTANT: Thank you for giving your valuable time, but there are no flights available based on your request.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for opting us, we hope to serve you again with better features.