Can Blood Types Change?
Blood group antigens are either sugars or proteins found attached to the red blood cell membrane. ABO blood group antigens are the most clinically important antigens because they are the most immunogenic. As red blood cell antigens are inherited traits, they are usually not altered throughout the life of an individual. There have been occasional case reports of ABO blood group antigen change in malignant conditions,ABO antigen alteration associated with acute myeloid leukemia. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5242122/

https://www.ncbi.nlm.nih.gov/pubmed/15135601 ( B to O change)

https://www.ncbi.nlm.nih.gov/pubmed/22270426 (New laboratory procedures and Rh blood type changes in a pregnant woman.)

A bone marrow transplant will replace the cells which make your blood cells with cells from the donor. Over about 3-4 months (life span of a red cell), your blood will become your donors type.