If you have a tile roof on your home and it is leaking, you should not jump to conclusions and assume that it is due to faulty tiles. This is because the leak may be originating from a poorly installed roof jack around a pipe or around an air conditioning unit.
The first thing that you will want to do is to climb up in your attic and try to see where the leak is coming from and bear in mind that water can travel over the melt paper for several feet before it comes into the attic.
If you can see the broken tile however; This does make your job a lot easier and the thing that you will want to do is replace the broken tile without breaking more while you are climbing on the roof. When you walk on a flat tile roof step on the bottom portion of the tiles and if you weigh over 200 pounds you may want to enlist the help of a lighter friend.
Another trick is to shove a couple of long 2X8s on the roof that you have covered on the bottom with carpet padding and use them to walk on to disperse your weight. One trick is to slide pieces of flat sheet metal under the damaged tile and use roofing plastic to glue everything back in place, which most of the time will do the trick.
If you are determined to completely replace the tile though, then use a flat bar to slip under the broken tile, cut or pull any nails and remove it. After you have done that then slide a new tile in place and use roofing plastic to glue it down. Do not start banging new nails into a preexisting tile roof or you will be right back where you started at short order with more broken tiles.