Xenobiotic metabolism: phase 1 reduction enzyme

Question

Phase biotransformation reactions can be oxidations, reductions or hydrolysis of the xenobiota molecule. Phase 1 oxidations are catalyzed by the cytocrome P450 enzyme, abbreviated with the CYP acronym: the active site of this enzyme is a prorphyrin ring in the center of which a $\ce{Fe(III)}$ atom is coordinated. When the enzyme binds to the substrate, the iron is oxidized to form the perferryl species $\ce{Fe^{V}O}$, where iron has the unusual oxidation state +5. At this point the iron transfers, through a radical mechanism, the oxigeno atom to the substrate, reducing to $\ce{Fe(III)}$ and restoring the enzyme. This is for oxidations. Instead, I would like to know how the reductions always catalysed by the CYP work. In the books it is reported that the reduction always takes place at the expense of the iron, which from $\ce{Fe(III)}$ is transformed into $\ce{Fe(V)}$. But at this point, how does the enzyme restore itself?