A gap in research exists that demonstrates how principals use their authority to make decisions and how that intersects with change management models. The purpose of the study is to examine how one elementary school principal has led change and how teachers perceive the effectiveness of the change. The study seeks to explore principal's and teachers' perceptions of the impact of the change on the school. Through a bounded, qualitative case study design, the researcher used several techniques to gather data: teacher survey, principal interview, teacher interview, and document analysis. Multiple sources of data were used to adequately shed light on the phenomenon. Using multiple methods will help enable deeper understanding. The data were analyzed to determine how one principal utilized bureaucratic, psychological, technical-rational, professional, and moral sources of authority for leadership. The researcher then looked at how these sources of authority intersected with common themes in change management models. The researcher examined the data by coding the sources of authority with numbers and the common themes in change management models in color. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]