You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Joseph Wright.

ASSISTANT: How may I serve you for the day?

USER: I am planning to visit Las Vegas to celebrate my birthday celebrations, can you please book me a ticket from DTW to LAS?

ASSISTANT: Sure, I will help you in booking. Can you please let me know your travelling dates?

USER: My preferable journey dates are from Sept 26 to Sept 28.

ASSISTANT: Is there any specifications for you?

USER: Yes, I need direct flight on this route.

ASSISTANT: Thanks for providing details, we are unable to provide flights on your preferable dates of journey.

USER: Ok, not an issue. I will find any alternate for this trip. Thank you for providing information.

ASSISTANT: Thank you for choosing us.