You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: I need to book a flight ticket to Washington to enjoy twilight tour with my colleagues on 10/12. Can you make a reservation with name William Thompson.

ASSISTANT: Sure, please mention me your airport codes?

USER: Sure, I need to fly from. It's a round trip to DCA.

ASSISTANT: Do you have any specifications?

USER: Yes, I need a halt in between journey. And it will be helpful if price limit is 200.

ASSISTANT: Can I know your travelling dates?

USER: Sure, my arrival date is on 10/14.

ASSISTANT: OK, please wait for few minutes.

USER: Sure.

ASSISTANT: Sorry, to inform you that there is no flight with your requirement.

USER: Ok, no worries at all. Thanks for your support.

ASSISTANT: Thank you for reaching us.