Fwd: upgrading a port with no maintainer

Dev, Suppose I wanted to upgrade a version of a port with no maintainer,say, http://www.macports.org/ports.php?by=name&substr=pixen, from version 2.2 to 3.0. How might I go about making the change on my local box (leaving the submitting a patch process out for the time being)? Is there a doc you could point me to? I'm familiar with how to perform this task in gentoo, but not yet very familiar with macports. - Kevin