I did this once and I was able to get it to work again after. I accepted a battle pet duel right as I used Blade of the Naz'jar Battlemaiden. It disconnected me and when I logged back in, I was the Naz'jar Battlemaiden where the pet battle was taking place! I was able to run around and kill monsters - others were able to see me and were wondering how I did it. The timing on this is particular difficult, it took me about 20 tries before I was able to do it again.
Here's the quest: Visions of the Past: The Slaughter of Biel'aran Ridge - Quest - World of Warcraft
Hope someone finds this useful.![]()