A quote from Michael Sherwin, O.P. (University of Fribourg) from his By Knowledge & By Love – Charity and Knowledge in the Moral Theology of St. Thomas Aquinas:

As a rational appetite, will differs from (merely) natural appetite by being an inclination that follows cognition, while it differs from sensitive appetite by being an inclination that follows intellectual cognition and by doing so from one’s free decision…It inclines toward universal good and those goods that are naturally ordered toward teh agent’s attainment of universal good. Second, Aquinas affirms in both his earlier and later works that the intellect has a certain causal priority over the will and that the intellect has a certain causal priority over the will and that the intellect moves the will by presenting the will its object. Third, Aquinas maintains consistently throughout his works that although on one level reason moves the will, on another level the will moves reason: the will has a role in shaping reason’s practical judgments. (p. 25, emphasis mine)

The third point is important and provides insight into Thomas’ teaching on the will. The intellect moves the will, but the will molds reason’s practical judgments. This shows that there is a dynamic relationship between intellect and will.