Edit copy

From NWNWiki

Edit copy is used to make a duplicate of an existing blueprint. When you select this option, you are presented with the properties of the item you are copying and this is the only chance you have to change the ResRef. (By default, a number is placed on the end of the existing ResRef like 001 to ensure it will be unique.)

When you save this dialog, a new blueprint will be placed in one of the blueprint categories.