There are rare instances when the kidney transplant recipient suffers brain death and in such cases, the kidney has been removed and replaced in the donor in cases of living donation. I am aware of one instance when the kidney suffered acute rejection and was returned to the donor. Otherwise, it is not possible to re-attach a transplant from a recipient back to the donor when they die of most other illness. The kidney cannot be replaced into the same anatomical site from which it was removed. It would have to be replaced into the lower abdomen, next to the leg. This is where all transplants are placed.