Mac OS X v10.5: Can I delete a partition without erasing the entire drive?

Hi! See THIS. Tom

yes. Open disk utility, select your external drive and click on the partition tab.
select the partition you want to erase and click on the - sign. The partition will disappear and there will be a big chunk of free space where it used to be.
you can add that free space to the partition immediately above the erased one by dragging its lower right corner down to cover the empty space. If the partition you erased was the upper most one, your can not reclaim the erased space short of reformatting the whole drive (and thus erasing all the data on it).

apdv1 wrote:
Can I delete an empty partition on an external drive and expect to keep the data on the other one if I am using Leopard?

Whatever you do, backup your data first. Stuff does happen.