How to change units armor type via trigger

[usfshihy]

i am trying to make a spell in which if the unit casts it, it changes it's armor type. I tried basing it off channel but I don't know what to do any further.Please help!!

+REP and credits for helpers!!!

 

[PurgeandFire]

You'll have to morph the unit to an equivalent unit of that armor type. See this tutorial for information on the morphing process:
http://www.hiveworkshop.com/forums/general-mapping-tutorials-278/hero-passive-transformation-198482/

So you'll have to make a different unit-type for each armor you want to support for each unit who may cast the spell. i.e. if you have a paladin and you want to switch between hero, unarmored, and light armor, you would make three versions:
Paladin (hero)
Paladin (unarmored)
Paladin (light armor)

And have transformation abilities between all 3 of them.

 

[RobertMKD]

If the caster is not a hero, you can replace him with an identical unit that has only a different armor.