Report to Undertaker Mordo at the Deathknell Graves in Tirisfal Glades.
Welcome back to the realm of the living. With the blessing and power of the Dark Lady, I have freed you from death's grip.
You are no slave, <name>. You are free to follow whatever path you choose from here. If you choose to serve the Dark Lady Sylvanas, I recommend you speak with Undertaker Mordo. You will find him behind me, in the graveyard.