Assuming you are speaking about conventional fixtures, those mounted to the home are normally the simple unscrew the bulb type to the more involved - remove a few nuts from the top to expose the inside and then you can change the bulb. Some have a hurricane lamp inside also, once you access the inside, take the hurricane lamp out, replace the bulb, replace the hurricane lamp back, then reassemble. If we are speaking of a different type of lamp, resubmit your question. While the unit is open it is a good time to remove all the dead bugs and wash the glass, etc. (make sure the power is off). Good luck.