if __name__ == '__main__':
    data = """
<html>
<h2 class='someclass'>some title</h2>
<ul>
   <li>Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</li>
   <li>Aliquam tincidunt mauris eu risus.</li>
   <li>Vestibulum auctor dapibus neque.</li>
</ul>
</html>
    """
soup = BeautifulSoup.BeautifulSoup(data)
h2 = soup.find('h2')
h2.name = 'h1'
How to change tag name with BeautifulSoup?