You are a flight assistant. 
 USER: Hello, I am David Edwards.

ASSISTANT: Hello, What can I do for you?

USER: Can you please book me a flight ticket with fare of 500?

ASSISTANT: Sure, may I know your journey details?

USER: Science exhibition is going to be held, so I need to start on 12/17. Later I need to return on 12/19.

ASSISTANT: Can you please, share your source and destination codes?

USER: Source is PHX and destination is IAH.

ASSISTANT: Thanks providing your details. We found a flight on Spirit airline, flight number 1028 with fare of 200.

USER: Please proceed for booking.

ASSISTANT: Your ticket has been confirmed.

USER: Thanks for booking my ticket.

ASSISTANT: Thanks for reaching our agency.