Originally posted by JakeTheBank
Technically, Ultron, as it took over Tony's body, would have a "soul" to speak of. You could argue that the lasso's nature of truth would even restore Tony back to his original form, uncorrupted by Ultron.
It can't undo non-magic transformations like it can magic ones- Silver Swan was cyborgized from one of Diana's friends, after all, and it took a long time and plenty of surgery to restore her.