No, within the human body, there are no known natural biological processes that can change the atomic mass of an atom by altering the number of protons or neutrons inside it.
The number of protons determines the atomic number of an element, which defines its identity. Changing the number of protons would result in a different element altogether, which is not possible through natural biological processes.
Similarly, while there are some instances of radioactive decay occurring in the human body due to the presence of naturally occurring radioactive isotopes, such processes typically involve the spontaneous emission of particles or energy, rather than the removal or addition of protons or neutrons to individual atoms.
However, it is worth noting that artificial processes, such as nuclear reactions or medical procedures involving radiation therapy, can alter the atomic mass of atoms by introducing or removing protons and neutrons. These processes are typically performed outside the body in controlled environments and are not natural biological processes.