Under Utah Code 76-3-402, a conviction cannot be reduced by more than two-steps.
Whether you need a one-step or a two-step reduction depends on what you want to accomplish and the level of the original conviction. For example, a third-degree felony requires only a one-step reduction to become a misdemeanor. A second-degree felony requires two steps. A class C misdemeanor requires only a one-step reduction to become an infraction. A class B misdemeanor would have to be reduced by two steps to become an infraction.
The court can grant a one-step reduction if the judge is convinced that the reduction is in the interest of justice – even over an objection from the prosecutor. However, a two-step reduction requires both the prosecutor AND the judge to agree that the reduction should be granted. Utah law prohibits a judge from granting more than just a one-step reduction without the prosecutor’s consent. Under no circumstances can a judge reduce the level of a conviction by more than two steps.