you need a blank cloak which you can skin and wear it over another cloak. They're available in SM
#Cloak wardrobe not working.
lost epoch
junior nest
Cloaks that provide stats cannot be changed to look like cloaks or wings that are worn above stat cloaks. You need a blank cloak or any other cosmetic cloak that you can then change to look like the master cloak. For the FWC Red Wings you need blank wings or another cosmetic wing item. You can buy blank cloaks and wings at the NPC Leann in Saint Morning near the Loadstar.