<p>Yeah, I'm pretty sure submatriculation is a readily available option, though I think it might depend on what you want to submatriculate into. </p>
<p><a href="http://www.college.upenn.edu/curriculum/submatriculation.html%5B/url%5D">http://www.college.upenn.edu/curriculum/submatriculation.html</a>
<a href="http://www.seas.upenn.edu/ugrad/submatric.html%5B/url%5D">http://www.seas.upenn.edu/ugrad/submatric.html</a></p>