Breaking control over Spawn

[Greymane]

When a creature such as a Shadow or a Vampire creates Spawn from their victims, the Spawn are undyingly loyal to their creator.

What methods (if any) can an outside party take to sever that connection? Aside from the death of the Spawn's creator, of course.

[Yora]

Spells that control undead could temporarily override the undeads loyalty. But when the spell ends, the spawn would again follow any command by its creator.