You might notice them temporarily browning a bit in some inhabitants from an increase in zooanthellae which block out the natural pigments of the specimens. If the reduction in light isn't too drastic, it shouldn't be too bad and they will expel some of the zooanthellae when the lights are back at their normal position so the effect isn't permanent. Most of your non-sessile stock will have little problem with the lower light, fishes might change their habitual patterns and either stay hidden more or come out more depending on if they're diurnal/nocturnal, anemones may move higher up in the tank depending on how much it effects them, almost all crabs and snails will fail to even care.