You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you at this moment?

USER: Patrick Hernandez here. Please help me out in booking the ticket from DCA to EWR.

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates for booking flight ticket?

USER: My trip dates will be 07/29 to 07/31.

ASSISTANT: Please hold on a moment, I will check flight availability in this route.

USER: Ok.

ASSISTANT: Sorry no flights are available in this route as per your requested dates.

USER: That's ok, not a issue. Thank you for informing.

ASSISTANT: Thank you for reaching us, have a nice day.