Reinstalling as x86-64 without format. Possible?

[elekktretterr at exemail.com.au]

I have an older DF installation from 2010(using HAMMER) which I'd like to
upgrade to x86-64. Is this possible without reformat? I don't have a spare
hard drive where I can move my /home. I have FreeBSD with ZFS on another
disk but DF can't write to that.

Is there a way to reinstall without formatting the hard drive?

Petr