At this time there is nothing that can be done. If someone goofs and they are a sole approver or have enough weight to approve for a cab you are screwed. There is no tech permission, no override of any kind. I just talked with peter.kruty about this very issue a couple of weeks ago.
Action Rules will not help you for this problem. You can manually recreate a new ticket but then it must go through all steps all over again.
It's a very big issue for me