The mage can convert Mana into Essence and channel it into a spirit.
If the spirit doesn’t want the Essence (its quality might be considered negative), it can contest with a reflexive Resistance roll. Each success allows the mage to convert one Mana and channel it as Essence. Unless he has a means of taking this Mana from another source (such as with the Prime 5 Siphon Mana spell), he must spend his own Mana.
Mysterium Rote: Word of Honor
The mages of the Mysterium use this rote to prove to a skeptical spirit that their pledge and bond is good, usually to coax it into a fetish or convince it to act as a familiar.