Can a defendant sentenced or placed on probation prior to Proposition 47's effective date have his or her sentence reduced?

Section 1170.18 identifies two ways a defendant sentenced or placed on probation prior to Proposition 47's effective date can have his or her sentence reduced. First, pursuant to section 1170.18, subdivisions (a) and (b), a defendant may file a petition if she or he is currently serving a felony sentence for an enumerated offense. Second, if a defendant has completed his or her sentence for an enumerated offense, the defendant must file an application to secure the designation. ( 1170.18, subds. (f) & (g); People v. Shabazz (2015) 237 Cal.App.4th 303, 308, 310-311.)