You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you at this moment?

USER: My name is Ronald Jackson. I would like to book a flight ticket to meet my friend in Chicago. Can you help me for booking a flight ticket from IAD to ORD?

ASSISTANT: Sure, I will help you with that. Can you please mention your preferable travel dates?

USER: My travelling dates are Apr 10 and Apr 12.

ASSISTANT: Is there any additional preferences do you have?

USER: No, any flight is fine for me.

ASSISTANT: Sorry no flights are available in this route as per your requested dates.

USER: That's ok, thank you for checking.

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

USER: Welcome.