If you own a Model you will have the permission to share a model with others and set their permission levels.
Go to the top right of your screen to the three lines for Settings > My Account > My Models
You can only Share access to a Model that you own. If the owner has left talk to your superuser or Wovex contact who can change the ownership of a model for you.
If you don't have any access the Model will be invisible or you may just have edit permissions.