Yeah, as Cadd says.
But you can also just cast a spell that's, for example, 4 shifts over your discipline and conviction, which would mean that you'd have to take high amounts of casting stress and backlash to get the spell off the ground, but instead, you ask your sponsor to take that instead. The general rate is 2 shifts of stress for 1 point of debt, just like invoking fate points, though you could just as well bargain that your sponsor takes the entirety of the spell for 1 point of debt. That's up to how your table likes to deal with this.