You are a flight assistant. 
 USER: Hello. I am Katharine Hall here.

ASSISTANT: Hello, how may I serve you at this moment?

USER:  I need to book my ticket from DEN to DTW. Can you please help me with booking a flight ticket ?

ASSISTANT: Sure, I will help you. Please send your travelling dates.

USER: My planned travel dates are from Apr 26 to Apr 28.

ASSISTANT: Do you have any class or time preferences?

USER: Yes, my return time should be in the evening.

ASSISTANT: Do you have any connection or airline preferences?

USER: I need a connecting flight in my journey.

ASSISTANT: Sorry, there is no flight available with your given requirements on your requested dates.

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

ASSISTANT: You are welcome, have a nice day.