http://www.AsktheBuilder.com founder, Tim Carter, demonstrates the safe way to remove patio tiles. Hammers are not recommended!
To prevent unbroken tile from getting broken, you need to cut away the grout from around the broken tile being removed.
Do not hammer the tile with the grout in place as the force transfers to adjacent tile breaking them in the process.
Grinders with dry-diamond blades cut away the grout fast.
Hand-held cordless chipping hammer tools with a 1-inch-wide chisel work well on softer tile.