You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: Could you please book a flight ticket from DCA to LAS?

ASSISTANT: Sure, may I know your travelling dates?

USER: My travelling dates are May 16 and May 18.

ASSISTANT: Do you have any connection limit?

USER: I need a single connecting flight.

ASSISTANT: May I know your name?

USER: My name is Kathleen Garcia.

ASSISTANT: Sorry, there are no flights found with your data.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you.