You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: Please help me in booking a flight ticket from DTW to DEN.

ASSISTANT: Sure, may I know the travelling dates?

USER: I will start on June, 26 and return on June, 28.

ASSISTANT: Do you have any connection limits?

USER: I would prefer single connection.

ASSISTANT: Is there any other requirement?

USER: I need to depart at evening time.

ASSISTANT: May I know your name?

USER: Brian Green here.

ASSISTANT: Please wait a moment.

USER: Sure.

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

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

ASSISTANT: Thank you for opting us.