You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I assist you?

USER: I would like to make a flight ticket reservation from IAD to DEN, can you please help me?

ASSISTANT: Sure, May I know the travelling dates?

USER: Sure, my planned travelling dates are Aug, 20 and Aug, 22.

ASSISTANT: Do you have any connection limit?

USER: Flight has to be with single connection.

ASSISTANT: Is there any other requirements?

USER: I want to travel at afternoon.

ASSISTANT: May I know your name?

USER: Anna Robinson.

ASSISTANT: Please wait a minute.

USER: Ok.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.