You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Can you help me booking a flight ticket from HOU to LAS?

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: I will start on 06/18 and return on 6/20.

ASSISTANT: Are you looking for a connecting flight or direct flight?

USER: I need a break in my journey.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Do you have any other requirements that you are looking for?

USER: I need to depart in the evening time.

ASSISTANT: Can you please provide your name to proceed further?

USER: I am Ryan Evans.

ASSISTANT: Sorry, there are no flights available at your request.

USER: No problem,thank you for the information.

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