How do I replace a low beam HID bulb on a 1999 BMW 528i?

I can unscrew the cap off the old bulb but then don't know what to do next. Do I need a special tool to unscrew the actual bulb? Help!How do I replace a low beam HID bulb on a 1999 BMW 528i?It is most likely spring loaded so "push in and turn"

grimaldis