@jkswcon, Welcome to Connect.
A patient with cirrhosis that has progressed to end stage liver failure might be referred for evaluation to see if they qualify for a liver transplant. During a liver transplant, the patient's diseased liver is removes and replaced with a healthy donor liver.
A liver can be from a deceased donor which is when a patient is placed on the transplant waiting list. My transplanted liver came from an annonymus deceased donor.
Or the liver can come from a Living Donor. When someone wants to be a Living Liver Donor, they donate a portion of their liver which is placed in the recipients body where the diseased liver had been. Both the donor's portion of the liver and the recipient's portion will regenerate to a full sized liver. It is an astounding miracle of medical science! Most living donors are related to the recipient.

@jkswcon, Does this answer your question? Are you being considered for a liver transplant? Are you thinking about being a a living donor? What are some questions that you want to ask?