Changing attack type through triggers?

Is it possible to change a unit's attack? I can easily change armor by using the upgrades, but there is no thing for weapon type. I plan to implement this into a current map I'm making.

For example, if a hero obtains a certain weapon and it is of fire type. Then, a trigger will change it's attack type to fire. If it changes or drops the weapon, then it will revert to normal or change again.

Even if you had an upgrade for an attack type, that wouldn't help you because you can't unlearn upgrades. The only way I see is having multiple versions of the unit with different attack types.

Orbs will help you.
I remeber there is 1 ability call "lightning" if i am not wrong, that will also change the missle art. By using triggers to add the ability for the hero that aquires an item it will change the missle art of the hero.

Ahaha, ahah, hahah, ahh...
No.
He means he wants to change the attack type the unit uses, such as piercing, normal, hero etc, unless I'm much mistaken.
The only thing I can see which is close is either to use Anitarf's idea, or you could have attack one and attack two with different damage types, and use orb abilities to switch between the two. Problem is, this would only allow two different damage types...

Guess i misunderstood this sentence. haha! sry..

I've used the multiple hero method but is there anyway to add hero abilities to a hero like in "Hero Builder Team Survival" where you choose the abilities in the beginging on a dummy unit and then the hero can physically add points to them instead of uping a dummy ability.

When you just do "Unit - Add ability" for a hero ability it gives the hero the level one ability and even if you do tome of retraining it does not get unlearned.

As far as I know, you can't add hero skills, but I'm not familiar with that map so I don't know how this was achieved there.

The way I would do this would be to use multiple units. You can't give a hero hero abilities via triggers (As far as I know), but you can just make all versions have the same abilities using the object editor, then use triggers to set the new hero's level and force it to spend it's skill points on the same skills it had before.

As far as I know, it's physically impossible to do what you're talking about. If I was going to make a system like this, I would probably do damage through triggers, with a variable for attack-type, and have a multiplier variable for the attack-types.