Step 1:  In your parent window document add a function

function changeURL(url)
{
    if( url == ""){
        url = document.location.href;
    }
    document.location.href = url;
}

Step 2: In iframe document call this function to change URL of parent window

parent.document.changeURL('http://www.google.com/');

 If you only want to refresh parent’s window, use the following statement.

parent.document.location.reload();