You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Paul Walker. I want to meet my brother on his birthday, can you please help me to book my flight ticket from IAD to ORD?

ASSISTANT: Sure, I am gleeful to assist you in booking a flight ticket. May I know your departure and arrival dates please?

USER: Sure, I will depart on Dec 12th and I will return back on Dec 14th.

ASSISTANT: Ok, do you have any class preference?

USER: No class preferences, I prefer for a normal-cost airlines.

ASSISTANT: Ok, please hold on for a minute.

USER: Please check for the single connection flight.

ASSISTANT: Ok, I have found a flight which is exactly matching to your requirements in the United Airlines and the ticket cost is 100. Can I proceed with the ticket booking?

USER: Yes, please book the ticket for me.

ASSISTANT: Ok, I have confirmed your ticket with the economy class flight and the flight number is 1005.

USER: Thank you so much for your help.

ASSISTANT: Have a safe journey. Thank you for opting us.