(3)No such person as aforesaid shall be dismissed or reduced in rank until he has been given a reasonable opportunity of showing cause against the action proposed to be taken in regard to him:Provided that this subsection shall not apply-(a)where a person is dismissed or reduced in rank on the ground of conduct which has led to his conviction on a criminal charge ; or(b)where an authority empowered to dismiss a person or reduce him in rank is satisfied that for some reason, to be recorded by that authority in writing, it is not reasonably practicable to give to that person an opportunity of showing cause.
