How do I install a soap dish in an already tiled shower?

I ve had to do this before and it can be done w/o removing the tiles , but you may not like it . I take a dremmel w/ a ceramic cutting bit and cut just thru the tile by holding it at an angle. Then carefully remove just this pc. Now this will only work on walls that have a cement backer to them. Then you thin set the dish or shelf into place after trial fitting it or course. Corner shelves will stay in place once set but soap dishes need to be taped for 24 hrs since most will fall out if not set just right. Tape off the outer area to be cut w/ masking tape and cut out the inner part. Use grout lines to your advantage and set shelf or dish on them if at all possible. Ant questions you can e mail me GL