I had to replace a couple of tiles in a shower where I had installed a safety bar for mom. Here is the video I checked:
I did things a bit different. I scoured the grout first with a tile grout saw making sure there was a “canal” for the blade to run. It also helped weaken the grout itself, a plus. And yes, the utility knife works like a charm.
After that and since holes were already made, I tapped the tile repeatedly but gently with a regular hammer till it cracked and fell. Don’t go gorilla or you may miss and screw a good tile or the backboard. No chisel, but a flat screwdriver just to help a stubborn piece fall without tapping it with the hammer but using it as pry bar.
And take it really slow with the hammer. you have all the time in the world, actually you may take under 5 minutes per tile. I patched the holes with a waterproof spackle designed for exterior and now I wait for it till tomorrow to dry before doing the rest.
Seriously, the utility blade trick is the key, it gave me a clean removal. And this is coming from one who has a long list of effed up tiles in his history 😀