You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Can you please book a ticket from DCA to BOS?

ASSISTANT: Sure, when are you willing to travel?

USER: My travelling dates are Dec 6 and Dec 8.

ASSISTANT: Do you have any preferences?

USER: I need a single connecting flight.

ASSISTANT: May I know your name please?

USER: My name is Jonathan Anderson.

ASSISTANT: Sorry, no flights were available at this moment.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for opting us.