So was testing graves.. and well notice the control two undead message after casting here.. And is the effect suppose to last till death or can it be changed out for another undead?

<680/680 782/992 453/581 13289tnl (5.75%) 6 AM> s
Grave of the Faceless Warrior


A beaten and sorrowful warrior kneels before the faceless grave.
<680/680 634/992 493/581 13287tnl (5.77%) 7 AM> c 'greater undead' ghoul
c 'wraithform'

A mourning warrior says 'He was the life of all, and now death has come..'

<680/680 634/992 493/581 13287tnl (5.77%) 7 AM>
You pace the graveyard, scanning for a proper corpse.

<680/680 434/992 493/581 13287tnl (5.77%) 7 AM>
Having chosen one, you begin the forbidden mantras of your ancient art.

<680/680 434/992 493/581 13287tnl (5.77%) 7 AM>
Coursing with power, you clench an outstretched fist, calling the spirit to awaken.

<680/680 434/992 493/581 13287tnl (5.77%) 7 AM>
A luminous cloud rises from the ground and disperses into nothingness around you.
You lurch as your body becomes insubstantial.

<680/680 404/992 493/581 13287tnl (5.77%) 7 AM>
Two greater undead are more than you can control!

>So was testing graves.. and well notice the control two
>undead message after casting here..

FNCR

>And is the effect suppose
>to last till death or can it be changed out for another
>undead?

You can't successfully summon another greater undead until your greater undead dies or is released.