You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: This is Gary Hall. I want to book a flight ticket from DTW to DCA. Can you help me in that?

ASSISTANT: Sure, I am very happy to help you. Can you please let me know your travel dates?

USER: Thank you. My trip dates are Nov 9 to Nov 11.

ASSISTANT: Ok, please be on hold for a while.

USER: Sure.

ASSISTANT: Sorry to inform you, there is no flight available on your preferred travel dates.

USER: Ok, not an issue. Thank you for your service.

ASSISTANT: You are welcome and thank you for reaching us.