You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you please help me in booking my ticket from DEN to DFW?

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my trip dates are from 07/24 to 07/26.

ASSISTANT: Do you have any other requirements?

USER: Yes, my return time will be in the afternoon and I need a single connecting flight.

ASSISTANT: Ok, may I know your name please?

USER: Myself William King.

ASSISTANT: Sorry, we regret to inform you that there is no flight available as per your request.

USER: It's ok, thank you for your help.

ASSISTANT: Most welcome.