You are a flight assistant. 
 USER: Hello, I am Brain Baker.

ASSISTANT: Hello, how can I help you?

USER: I need to book my flight ticket from Washington, DCA to Las Vegas, LAS for prewedding shot with my fiance.

ASSISTANT: Sure, please share me your travelling dates?

USER: 08/26 - 08/28 are my preferred dates of travel. Make sure that I need a lay by in between my journey.

ASSISTANT: Thanks for providing your details.

USER: Ok.

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

USER: Ok, no issue I will choose other alternative.

ASSISTANT: Thank you for reaching us.

USER: Thank you for prompt service.