Hmm.

Way is quite complicated, but...
a:
You can change partitions, and if lilo will make sth wrong, boot machine with knoppix or other rescue, chroot to disk /, and reissue lilo
b:
You can make grub bootfloppy, and use it to start linux. Grub is for some reasons better than lilo, because it has no hardcoded files. It has a parser during boot and should not fail when changing partitions (as far as letters remain the same)
c:
If you have eg. everything on Linux on /, you can make another partition and mount if eg. to /home, or /usr or anywhere. It is sometimes good idea to split system into partitions, as for security reasons, backups and so.
d:
You can also change sizes of any partitions except one containing /boot whenever you want - lilo has nothing to them.