Source: Mage: the Awakening p322
Many of the spells described in Chapter Three: Magic can serve a double role as Numina.
To use a spell in this fashion, simply convert the spell’s rote dice pool to an appropriate trait roll for the spirit.
For example, to use the Life 4 “Enfeeblement” spell (p. 189) as a Numen, roll Power + Finesse instead of Strength + Intimidation + Life. (Note: There is no Arcana equivalent for a spirit, so its dice pool consists simply of one trait added to another trait.)