How to save a ref variable for later use?

So this works..

public MyClass(ref Apple apple)
{
    apple = new Apple("Macintosh"); // Works fine
}

But is it possible to do something like this?

private Apple myApple;

public MyClass(ref Apple apple)
{
    myApple = apple;
}

public void ModifyApple()
{
    myApple = new Apple("Macintosh"); // does not change the input variable like the first example did
}

When the ref variable is copied to the member variable myApple it appears to lose it's 'ref-ness' and re-assigning it no longer changes the input variable. Is there a way around this?