You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Karen Collins.

ASSISTANT: How may I best assist you today?

USER: Could you please help me to book an economy class ticket within the fare limit 500 to San Francisco?

ASSISTANT: Sure, please mention your dates of journey.

USER: I would like to start on Oct 30th and my return date will be on Nov 1st.

ASSISTANT: May I know your source and destination airport codes?

USER: My source and destination airport codes are IAD and SFO.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: We found a connecting flight with UA airline and 1012 flight number with a fare of 100. Shall I proceed?

USER: That's fine, you can book the ticket.

ASSISTANT: Your ticket is confirmed with an economy class.

USER: Thank you for being my helping hand in booking.

ASSISTANT: Thank you for supporting us.