Lighting acclimation essentially just means to control exposure to the new bulb. You can do this via several methods.
1. Raising the canopy.
2. Using a light diffuser (e.g. "eggcrate")
3. Shortening/staggering the photoperiod.
New bulbs emit different wavelengths and intensity. Light-sensitive organisms like corals may react negatively to the change. Results include retracted polyps, bleaching, and death. Controlling and limiting exposure to the new bulb slowly builds tolerances to the changes in parameter. It also allows the new bulbs to break in.
It's advisable never to change all your bulbs at once. Stagger the bulb change to at least a month apart to minimize unncessary stress.
admittedly, it's the least desirable method (hence, it being in the last suggestion). It should help some. It's like smoking less: acute damage is done everytime you smoke, but reducing usage will prevent chronic damage.