The Supreme Court has ruled that Corporation are individuals back in the 1800's.
Recently, the SCOTUS ruled that Corporations cannot be prohibited from political contributions because they are individuals.
If you want to change this, a new Constitutional Amendment (the subject in this article) must be passed by both Houses of congress and signed by the President.
It must then be voted on and approved in 39 States.
I would vote on it myself if I am still alive.