I'll answer that because in my previous life, we had cases like that.
It used to be that we could. Someone was released. They decided to take a voluntary release rather than wait around for a medical decision, and we found out that it would have been better for benefits and all that, so we used to change it retroactively. Several years ago the lawyers said that was illegal, and I don't know where that is now. I would say that you would have to go back to the CF and to legal people in the chief of military personnel's branch to find out if they can still do that.