Need help with changing armor type or nullifying damage received

[Player]

When a time based spell is cast (ex.: Slow) the affected unit's armor changes to another type for the duration of the spell. After the spell's duration is up, this unit's armor returns to the "original" armor type of the Unit.

Or in case it is easier:

Need a system/way any damage taken by the unit affected by the spell should be reduced to 0 for the duration of the spell only.

Any questions?

 

[Kadabra]

Use the Damage Detection system from bribe