Converting life cycle during early flowering

Ok i was wondering what is the best way for a person to change the light cycle during flowering. For example if light come on at 7 am and go off at 7pm. Then they need to change the light cycle so lights come on at 7pm then off at 7 am. Would you just turn them on/off an hour later every day , for 12 days till till you make the full adjustment. Or can you do it several hour at a time for several days to achieve it faster? Or can you just not turn lights on at all the next morning . Then turn them on when 7pm rolls around? Was wondering which would be the best and the least stressful to a plant in early flowering.