Teacher preparation programs have been slow to answer calls to prepare teachers for the online learning environment, leaving many online teachers needing to learn on the job. However, little research has examined how online teachers grow as educators while teaching online. One way to better understand this growth is to examine the changes online teachers make in their instruction and their rationales for making them. In this qualitative case study, we surveyed online teachers three times during an academic year regarding their instructional changes. Participants described these changes and categorized them on a modified PICRAT matrix to indicate if the changes made student learning more passive, interactive, or creative (PIC) and whether the changes replaced, amplified, or transformed previous activities (RAT). Teachers then provided a rationale for making their changes and shared perceived impacts. The majority described changes that focused on amplifying learning activities or making learning activities more interactive. Changes also tended to focus more on student-content and student-teacher interactions than on student-student interactions. Many of the provided rationales for making changes focused on increasing learners' affective, behavioral, and/or cognitive engagement. Teachers perceived these changes to be largely successful in having their intended impact.