Of course you can. All you have to do is strip the stain off them, which you can do with them on the wall. You will have to take off the doors and hinges to do this. Strip off the stain off cabinets and doors then re stain them in whatever shade you like. Messy, time consuming but for a very low cost you can change the whole look of the cabinets. I would also put a polyurethane coat over the cabinets once you stain them to protect them, just like you would a wood floor. Good Luck with this.

yes, first you need to sand down the cabinets, not completely just so they are rough so that they will accept color. second, you should get the desired color of stain from you hardware store and some foam brushes. make sure that the area is clean and dry before you use any product on it. apply one coat of stain evenly, wait for it to dry for about 10 min or so. wipe off the ecess with a lint free cloth, let dry for 4 to 6 hrs. “this is not a one day event” repeat these steps untill you get the color you want. after the last coat dries you should apply a polyurethane for added protection.

Yes. You will need to remove any sealcoat (polyurethane, shellac, varnish etc) and then sand. Going darker is a lot easier than trying to get it lighter. You can remove the doors and stain the frames in place. Follow the directions on the stain container. I like the Minwax Polyshades since you stain and finishcoat in one step.