Ceramic tile is one of the more durable kinds of tile, especially if it's glazed and has been properly cared for. If you want to take the tiles off one wall and apply them to another, it is possible, but it's a lot of work to get them off the walls undamaged, so make sure it's worth it. If the tiles are unique and you can't just buy replacements, you'll need to extract the grout and the tiles one by one and clean them up for reuse. Make sure you only use them on walls, not floors, as wall tile isn't suitable for foot traffic.
Extract the grout from around the tile you want to remove, using a grout saw. Score and dig at the grout with the sharp edge of the saw, breaking into the surface and gradually digging down. Remove the grout from all around the tile, taking care not to scratch or chip the tile or the surrounding tiles.
Hold a steel putty knife into the line on one side of the tile, with the flat end pressing against the base of the tile at an angle.
Hammer gently at the back of the putty knife, getting it under the edge of the tile. Pull the knife out, move it to another part of the tile, and repeat.
Continue working your way gradually around the edge of the tile, tapping the putty knife between the tile and the wall, until enough of the mortar loosens to release the tile.
Use the putty knife to clean up the wall, scraping off the residual mortar and getting it flat and smooth.
Scrape the back and sides of the extracted tile with a razor scraper, removing all the residual mortar and grout. Don't scrape the face of the tile.
Repeat the process for each tile that you want to salvage. Reuse the extracted tiles by spreading thin-set tile mortar over the new wall with a notched trowel. Press the tiles into place with 3 mm (1/8 inch) of space between them. Let them set overnight, then spread grout into the spaces with a grout float, wiping up the excess grout with a damp sponge.