You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello. How can I assist you?

USER: I am Justin Gonzalez. Can you help me in booking a flight ticket from IAD to LAS?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: May I know you travelling dates?

USER: I want to travel on 12/16, and return on 12/18.

ASSISTANT: Do you have any preferences?

USER: I want to depart at evening time, and need a connecting flight.

ASSISTANT: Thanks for your details, there are no flights found on your data.

USER: Ok, no issues. Thanks for the information.

ASSISTANT: Thank you.