Most models you can access the tail light bulb through the trunk or back hatch area, there should be a garnish cover that can be removed to access the light bulb connector most can be removed with a quarter turn.
Unfortunately, all makes and models have different designs for tail lights. Some times, you will see screws in the lens itself that will allow you to remove the assembly and access the back, where the bulbs are. Some times you need to go through the trunk. You may have to pull some of the carpet back to get to the bolts that hold the light assembly in. The assembly may require some firm (yet gentle) pulling or prying. Once you get the lens out, it's usually as easy as turning the bulb about a quarter turn and it should come out. Be sure you are putting in the correct type of bulb. As always, if you need help, ask for it.
〉 Answered on Feb 5th, 2008 by Suzanne Grego, Technician at City of Philadelphia Fleet Management