Depends on the model. I've seen both styles of expanders on ITM stems. remove the expander bolt, then remove the stem. that should give you a good view of the expander.

Thread the expander bolt in from the top. Then tap the bolt on the appropriate side to straighten the expander. Once straight, thread the expander bolt in from the bottom of the steerer tube and drive out with a hammer. I assume the hole is big enough to accept the expander bolt.