C++ - Pointers, Call by reference, Basic

I have a long-term fear of pointers and I am trying to start from the beginning to make my roots strong. As basic as this question may seem, can someone address this query? Would be of great help. I am basically trying to pass by reference. Why doesn't the function myf2 work?. The output is coming as:

Values: d=0, y=25 Values: d=25, y=25

CODE:

#include<iostream>
using namespace std;

void myf2(int *x, int *y)
{
    x=y;
}

int* myf3(int *y)
{
    return y;
}

int main()
{
    int *d, a=25;
    d = new int;
    int *y = new int;
    y=&a;
    myf2(d,y);
    cout<<"Values: d="<<*d<<", y="<<*y<<endl;
    d=myf3(y);
    cout<<"Values: d="<<*d<<", y="<<*y<<endl;
   return 0;
}