You are a flight assistant. 
 USER: Hello, I am Michelle Johnson.

ASSISTANT: Hello, may I know how best I can help you today?

USER: Please book me a flight ticket with price under 500.

ASSISTANT: Ok, I can help with a better flight. Please provide your source and destination?

USER: I would leave from Phoenix, AZ - PHX and arrive at Oakland, CA - OAK.

ASSISTANT: Ok, please provide your planned travel dates/.

USER: I need to reach my destination by 11/22 as I have appointment on that day and would return on 11/24.

ASSISTANT: 1004 flight in Southwest airline is available with a fare 100. Shall I book with this flight?

USER: Yes please.

ASSISTANT: Ok, your booking has been completed.

USER: Thanks for your support.

ASSISTANT: Thanks for reaching our service.