Well, it doesn't work like that. What they proposed in that blog post is only to see the scene, and they even gave a warning about not saving afterward, as you will have a mix of flags.
If you want to reverse a quest, you need a proper save edit.
Here I discussed that quest a long time ago - you can also manipulate the quest array by console - somewhere in the save edit thread, I discussed that as well. What I do not know is what flags need to be changed/deleted, even if you redo the quest.
If you provide a save file (and if I’m bored), I could investigate that.