Assuming it's a quill stem, you need to loosen the bolt at the top of the stem, then tap it hard with a mallet to loosen the expander bolt inside. The stem should them come out easily. You can then undo the headset to remove the forks.
@bracestower started
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Assuming it's a quill stem, you need to loosen the bolt at the top of the stem, then tap it hard with a mallet to loosen the expander bolt inside. The stem should them come out easily. You can then undo the headset to remove the forks.