What happens if somebody needed an organ transplant their body might reject the donorswould doing that for a real organ transplant actually work?

Rejection can happen: There is always chance of rejection.....though significant improvements in transplantation......no specific or selective treatments are available to avoid any rejection....however, those rejections are greatly manageable now a days with exception of very few percentage.....it is because of great improvement in pretransplant work up.....and post transplant managements, follow up