You can’t. You have to faff around with artboards.
But… There is a quick-ish way to do it if you have Indesign.
- Drop your multi-layered Illustrator file into InDesign (Ctrl+D)
- After positioning image on a page
- Make a duplicate (alt + drag with the mouse on Pages panel)
- Right click on image
- Select manage layers (对象图层选项 duì xiàng tú céng xuăn xiàng)
Fin.
Solution found here (Thanks Creather).