According to Canadian researchers, newly discovered enzymes can transform blood type, such as type A to O.

Source: CBC News

So, does the personality also change?
The ABO blood group substance is most frequently expressed in the stomach and intestines, and it is distributed not only in the body but also in most of the body.
Even if the blood type of erythrocyte changes, the blood type of the brain and nerve does not change - as it is.
This is the same with bone marrow transplantation.