DMH-Online

NWScript:

void main()
{
//Declares the PC as oPC
 object oPC =  GetNearestCreature(CREATURE_TYPE_PLAYER_CHAR, PLAYER_CHAR_IS_PC);
//Declares the target with this script as oGuard
 object oGuard = OBJECT_SELF;
//Declares the target that's tagged as oHostileToPlayer
 object oHostileToPlayer = GetObjectByTag("hostiletoplayer");
//Declares oItem as the tag on your armor, in this case, the tag is guardarmor
 object oItem = GetObjectByTag("guardarmor");
//Declares the chest slot as the nArmorSlot
 int nArmorSlot = INVENTORY_SLOT_CHEST;
//Checks to see if player(oPC) has the right armor(oItem) in the right slot(nArmorSlot)
   if (GetItemInSlot(nArmorSlot, oPC) == oItem)
//If true, do nothing
    {
    }
//If false...
   else
//Set oGuard's faction to HostileToPlayer
    {
     ChangeFaction(oGuard, oHostileToPlayer);
    }
}