You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you?

USER: I am Betty Lewis, I need a connecting flight from Las Vegas. I have a meeting with Board of Directors, in DCA. Can you help me in booking a ticket with a price of 200?

ASSISTANT: Sure, may I know your travelling dates?

USER: I have to stay there for couple of days, that is from 04/03 to 04/05.

ASSISTANT: Kindly mention your origin airport code?

USER: I am from Las Vegas, LAS.

ASSISTANT: Sorry to inform that, we have no flights available with your request.

USER: Ok. Thanks for providing some information. I am glad at your service.

ASSISTANT: Thank you for approaching us, have a nice day.