I hope I'm wrong but it seems there is no way to undo an error in a Co-Edit session. Whole branches can be deleted accidentally with the only recovery (I can find) being to not accept the changes back into the main document.
I have a subscription to allow me to share and edit session, but I'm not sure the solution is ready.
I have a subscription to allow me to share and edit session, but I'm not sure the solution is ready.