I would agree with revhtree and slowly acclimate them. The only time I do not acclimate my corals to lighting ( I ALWAYS acclimate them to water params) is when I purchase them from a LFS
in my area and the tank is pretty much identical to mine in lighting output.
If you do not acclimate them and the light is to much for them you could at best just bleach them some and have them be unhappy for awhile and at worst completely kill them.
One way is to keep the lights on for shorter periods working your way up, although some still say that burned for an hour or burned for 8 hours, your still burned. Another way is to move the lighting higher up above the tank if possible and slowly lower it.
And finally I have heard of people buying sheets of the screen door mesh and layering that up and slowly removing a sheet every few days.