Spirit > Mastery > Haste > Crit.
If the item has no Spirit but has Crit and Mastery then you reforge the Crit to Spirit. If the item has Haste and Spirit, reforge the Haste to Mastery.
If the item has no Spirit but has Crit and Mastery then you reforge the Crit to Spirit. If the item has Haste and Spirit, reforge the Haste to Mastery.