Add and equip item when PA piece health <= 0

[gob2]

What it says. I would like a script that when a PA piece (we'll call it "PAa") on an NPC reaches 0 hp; the following happens:

 

1. The PA piece (PAa) is unequipped

2. Another PA piece (PAb) is added to the NPC's inventory from a leveled list.

3. The PA piece (PAb) just added is equipped by the NPC.

 

Can someone show me how to do that? Thank you.