If a cat just has to be shaved you can do it but you should be warned it could change their personality. They may hide for quite a long time but sometimes it cannot be helped if they have knots or something in their fur.
You can be seriously hurt if you attempt this alone so you should always contact a groomer or vet for this procedure. It is probably pretty pricey as well.
My friend rescued a Persian and had it shaved - all but its head. She (the cat) didn't seem to mind. IMO she was happy to get all that stuff off of her and have some air on her skin.
I have shaved many cats and have had the Vet. help on occasions. I have an old long hair cat that I shave regularly as she is unable to groom herself properly and she is now diabetic, so we are keeping her flanks shaved so I can give her insulin shots. I also have another long hair cat that I have to give regular butt cuts to so she doesn't get all messy at the back end. I had to stick her in the sink to bathe her when that happened and she was a real trooper - NOT ONE SCRATCH!!!!
I used to do this on a regular basis with my Persian...always made him more active and playful like a kitten. The cut grows out nicely so you don't have to keep it up in the winter if you live in a cold climate.
