You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you today?

USER: I want to fly from LAS to DCA. Can you book a ticket from that route?

ASSISTANT: Sure, can I know your good name please?

USER: Sure, Helen Nelson here.

ASSISTANT:  When you are willing to travel?

USER: My planned travel dates are 09/19 and 09/21.

ASSISTANT: Do you need direct flight or connecting flight?

USER: I want a flight with single connection.

ASSISTANT:  Would you let us know if you have any other preferences?

USER: No more, thank you.

ASSISTANT: Sorry to say that, there are no flights available on the routes of your journey.

USER: No issues, thank you for the information.

ASSISTANT: Thank you for choosing us.