FC2 install - Multiple devices labeled /

[John Fleming]

Newbie here - I've used dd to copy hda to hdb.  At the outset of upgrading
FC1 to FC2, anaconda complains that "Multiple devices on your system are
labeled /.  Labels across devices must be unique for your system to function
properly.  Please fix and reboot."

What's the best way to rename or otherwise treat hdb so that I can proceed
with the upgrade without destroying my hdb backup?  Thanks - John