Which runtime?
For example, in java/libGDX, you would do this:
int swordSlotIndex = skeleton.findSlotIndex("sword slot");
Slot swordSlot = skeleton.slots.get(swordSlotIndex);
swordSlot.setAttachment(skeleton.getAttachment(swordSlotIndex, "short sword"));
Note that skins can be combined and picked from. Just because you need to mix and match doesn't mean Skins isn't a good solution.
Skins also makes it work better when you are also animating those slots.
