Hi Treforda11,
The best and simplest way of dividing your peace lily is by using your hands. Gently pull apart the peace lily into clumps and pot up into fresh house plant compost. Choose a pot that is about two inches bigger than the root ball. Plant you new peace lily at the same level as it was in the original pot leaving about half an inch between the rim of the pot and the surface of the compost.
April is a good time to divide and re pot your peace lily. Feed from April until the autumn with a house plant feed.
Hope this helps.
Happy planting.