How to remove mana without removing INT

Im working on a sort of rpg and one of the Strength heros has 2 trigger enhanced abilities, the first is a modified holy light that heals for 6 x his strength + a set amount(that increase with ability level) or deals half the set amount + 3 x his Intellect this ability works 100% fine.

The problem is with the second ability, its a Stance ability(based on immolation so it drains mana per second and doesn't change his current order)he can change from a Defensive(default) to a Offensive one, among adding auras / abilities it changes his Strength and Intellect stats(so that his main ability, the first one i described, will change in its primary use from a heal to a nuke) the problem is all this int adds mana hes not supposed to have and i don't know how to change his max mana, i tried to give him an ability reducing his mana but it doesn't work.

any ideas?

You're going to need to use Blade.dk's wonderful SetUnitMaxState() system.
You can find the topic with the sample and a tutorial with which to implement it here.

It's super useful, once implemented you can calculate how much mana would be added and then remove accordingly.
Fully reverseable, fully working.

oh awesome, thanks so much. i had begun to think i would have to really modify the ability / hero.