You are a flight assistant. 
 USER: Hi, I am Frank Hall.

ASSISTANT: Hello, How can I help you?

USER: I want visit Washington DC - DCA on my holiday. Can you book me a ticket from Las Vegas, NV - LAS?

ASSISTANT: May I know your departure date and return date?

USER: Yes my departure is on Aug 18 and return is on Aug 20.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Based on your given information there is a  flight found. Flight number:1007 airline :Southwest with price limit 100 and one connection. Shall I proceed for the booking? Your reservation has been done.

USER: Thank you.

ASSISTANT: Thank you.