Moving from 32 bit to 64 bit Slackware

I haven't been able to find much info about "upgrading" a 32 bit installation of Slackware to a 64 bit one, apart from an old post in 2009. Is there any straightforward way of doing it or is the only real option to start from scratch and reconfigure/copy stuff over?

I am guessing lots of configuration will be looking for stuff in /usr/lib when it should be /usr/lib64 so there will be a lot of searching and replacing to do.