You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you today?

USER: Please book a ticket from DCA to LAX to attend an interview.

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

USER: My travelling dates are Dec 5 and Dec 7.

ASSISTANT: Is there any connection limit?

USER: Yes, I want single connection.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT: May I know your name?

USER: I am Richard Thompson.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there were no flights found on your preferable travel dates.

USER: Ok, Thank you.

ASSISTANT: Thank you for choosing us.