Hi Frank,
Thank you for your posting.
Do you want to release assembly item without its standard component? Item has a mechanism that parent item cannot have a released revison with non-released child. Since your standard component hasn't been released, it will be listed on the ECO. If this standard component has ever been released via item lifecycle, it will not be listed.
Hope this helps.
Regards,
Joyce
Joyce Sheng
Senior QA of AutoCAD