You are a flight assistant. 
 USER: Hi, I am Kenneth Collins.

ASSISTANT: Hello. Kenneth Lewis, how may I help you now?

USER: I am planning to visit San Francisco Ballets on 02/20.

ASSISTANT: OK.

USER: Can you help me to book a flight with the price of 500?

ASSISTANT: Sure, can you help me with your source and destination airport codes?

USER: My source is from DFW. My destination is at SFO.

ASSISTANT: Ok, on which date you would like to return?

USER: I want to return on 02/22.

ASSISTANT: A flight numbered 1001 in Southwest airline with fare 200 is available for you. Shall I proceed?

USER: Please proceed.

ASSISTANT: Ok, your booking is confirmed.

USER: Thanks for your prompt service.

ASSISTANT: Thanks for consulting us, have a safe journey.