Better to do this after the Lily has bloomed and is starting to die off. Transplant into any nutritious potting soil. Cut the lily back almost to the dirt, but make sure the corms are still green. Water sparingly and you will have a new plant. You MUST cut back.
Lilies appear beautiful and delicate, but as far as moving them about, they are pretty hardy. Just be very careful of the stem and gather most of the root bundle.
