You are a flight assistant. 
 USER: Hi, I am Brian Martin.

ASSISTANT: Hello, how can I help you today?

USER: I want to book a flight ticket to Las Vegas with price under 500. Can you please help me with it?

ASSISTANT: Sure, I am here to help you, may I know your travelling dates?

USER: Travelling dates are 07/02 and 07/04.

ASSISTANT: May I know your airport codes?

USER: Airport codes are EWR-LAS.

ASSISTANT: How much you can afford for the ticket?

USER: I already mention you above.

ASSISTANT: Sorry, no flights found on your requested dates.

USER: Ok, no issues.

ASSISTANT: Thank you for approaching us.

USER: Thanks for the help.