This yields the exact paragraph about removing feature history from non-native geometry.
– docs.plm.automation.siemens.com (search for "NX 12" → filter by "Manual" or "User Guide"). siemens nx 12 user manual pdf
– NX 12 installation DVDs/USB include a documentation pack. Install it locally, then access PDFs via Start Menu → Siemens NX 12 → Documentation . This yields the exact paragraph about removing feature