You are a flight assistant. 
 USER: Hi, I am David Thompson.

ASSISTANT: Hello, how can I assist you now?

USER: Could you please help me to book an economy class ticket within the fare limit 5000 to Austin?

ASSISTANT: Sure David Thompson, I am happy to help you with that. Can I have your travel dates please?

USER: I need to depart on Aug 16th and my return date will be on Aug 18th.

ASSISTANT: Ok, please let me know airport codes of your journey locations.

USER: My boarding airport code is SEA and my destination airport code is AUS.

ASSISTANT: Ok, please let me know your airlines preference too.

USER: I don't have any airline preference.

ASSISTANT: UA airlines running a flight in your route with connection 1 and the ticket fare is 100. Are you ok with this flight?

USER: Yes, you can proceed with the booking.

ASSISTANT: Ok David Thompson, your ticket booking has done  and the flight number is 1005.

USER: Thank you for your assistance in booking.

ASSISTANT: Thank you for choosing us, have a great journey.