If you have a portfolio, bring it along with you to the interview. The bookers will review your book first (if you have one) and then may request a few Polaroids or "digitals" of you with minimal hair/makeup. They may or may not inquire about your work history within the industry. I would drop off a comp card as a reminder for a call back if they don't sign you on the spot. Typically, if they want to represent you they will offer you a contract on the spot.