You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Rebecca Walker. Can you help me in booking my flight ticket from DEN to DCA?

ASSISTANT: Sure, I will help you to book a flight ticket. Can you please share me your travelling dates?

USER: My trip dates will be May 27th to May 29th.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: Ok, may I know your arrival time and departure time?

USER: My depart time is in evening, my return time is in the morning.

ASSISTANT: Sorry, no flights are available on your route.

USER: Its ok, thank you.

ASSISTANT: Welcome, have a nice day.