I’ve discussed this with two different GMs and apparently, it’s not possible to undo the selection. I don’t believe that it’s not possible. I believe the devs simply won’t allow it.
I suppose their hands are tied.
GM1
"Hey there Rechab,
I’m Game Master [redacted]. I hope this message finds you well.
During the questline The Fate of Saurfang, you will be offered a choice to side with Sylvanas or Saurfang by the NPC Zekhan. Depending on your choice, an additional dialogue box will alert you to the consequences of your choices.
Customer Support is not able to assist if you change your mind or make a mistake when choosing your options. If you do this quest chain on a different character, however, you can make the other choice for that character.
**In short if you choose the “I will not betray my Warchief, troll.” option, your character will not be able to get the Worn Cloak toy. There is a dialogue box that confirms that. The warning only appears when you are choosing the dialogue option. When you choose to pursue the quest choice, there is no warning window of any kind. **
If you progressed past the point of picking a side, you have to remain on the chain that you picked and do not have an option to switch. I do apologize. But I hope this information helps!
If you still need to contact us, please feel free to do so! We want to make sure that we have covered all of your questions thoroughly so if there is something that was missed, you can click the Need More Help button, and we will be notified. Please let us know any details about how we can further assist you with this issue. Otherwise, you can close this message out as resolved.
Thanks again for your time. Take care!
-[redacted]"
GM 2
"Hello there Rechab,
This is Specialist Game Master [redacted]! I understand that you had an issue with supporting the Dark Lady instead of Saurfang.
I’m sorry to hear the wrong option was chosen here!
Unfortunately this choice is a one time option, and you are not able to change it after the fact. This is not something that anyone will be able to reset or undo.
If you would like to see the option to change sides afterward in the future, I would definitely recommend letting the developers know directly that you would like the option to exist by posting either a suggestion in game or posting to the questing to forums to let them know what changes you’d like to see.
I’m sorry that we weren’t able to assist with your issue. I understand how frustrating that can be. If you have any other problems that we could take care of in the future, please don’t hesitate to let us know."
My response to the second…
I don’t believe that it’s not possible to change. It’s nothing but computer code! It can definitely be done. I suppose the devs won’t allow it to be done is what the issue is. I hope all the devs involved receive a large chunk of coal in their stockings this Christmas! It was a dirty lawyer trick the way they did the quest.
Now my main has been corrupted forever without recourse. I hope the Dark Lady spares him! Please forward all of the tickets you get for this matter to Ion’s desk and have Lore read them all aloud!