How to Re-Label / Re-create filesystems?

[Wayne]

Could someone point me to instructions or offer suggestions on how to 
re-configure file systems on a 6.x system?

When I installed from CD, I used the sysinstall menu, which I guess 
actually calls bsdlabel and newfs (??)

I want to delete two filesystems, and recreate one large one in the same 
space.  I tried dropping to single user and running sysinstall, but it 
protests it can't write to the device... even when I only had things 
mounted read-only.  Can I safely use the boot CD to do this?  I don't 
want to experiment too much and clobber the whole drive!

  -Thanks,  Wayne