Yes, hair can be transplanted from one area of the scalp to another. The transplanting of the hair is not the issue. It is having enough hair to redistribute to the bald/thinning areas. There are currently two widely used methods of harvesting the grafts. The older method, follicular unit strip surgery, involves cutting a strip of hair from around the sides and back of the head about 1/4" by 9" long. Then dissecting it into 1,2 and 3 hair grafts to transplant under a microscope. Of course the scalp in th area of th surgery has to be stapled together. The problem comes with tighter scalps limiting strip surgeries and limiting the number of grafts. Since the scalp is rejoined where the strip is extracted, the hair on the back/sides is as thick as ever and the transplanted top can never be as thick. The newer method is FUE(follicular unit extraction), also know as the wood’s technique. The 1,2 and 3 hair transplants are removed individually over a large area of the back/sides, thinning the back/sides. There is no problem with scalp tightness limiting grafts. Also, less invasive as there is no cutting with scalpels involved and no stapling of the scalp together. Only a topical anesthetic is used. FUE tends to be more expensive than a strip surgery to harvest the grafts. There is a lot of information on the internet on both methods. The transplanting of the grafts is largely the same. It is the way the grafts are harvested that differs. Hopefully, in the not too distant future, an unlimited supply of grafts to transplant will be able to be grown in a lab.
Good Luck!