You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. how may I address you?

USER: Can you help me to book a flight ticket from DCA to IAD?

ASSISTANT: Sure, on what dates will you be travelling?

USER: I will start on June, 19 and return on June, 21.

ASSISTANT: How many connections do you need?

USER: I need direct flight.

ASSISTANT: Is there any other requirements?

USER: No.

ASSISTANT: May I know your name?

USER: Rebecca Baker.

ASSISTANT: Thanks for providing your details Rebecca Baker, we regret to inform that there are no flights available on the dates you requested.

USER: It's ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.