Enterprise resource planning (ERP) projects, a type of complex information technology project, are very challenging and expensive to implement. Past research recognizes that escalation, defined as the commitment to a failing course of action, is common in such projects. While the factors that contribute to escalation (e.g., project conditions, psychological, organizational, and social factors) have been extensively examined, the literature on deescalation of projects is very limited. Motivated by this gap in the literature, this research examines deescalation, that is, on breaking the commitment to the failing course of action with a particular focus on ERP projects. This study is organized as a single-case study of a complex ERP project that was undertaken after a merger of two organizations. It examines how the project team members' sensemaking is implicated in deescalation. Applying sensemaking as a theoretical lens, this engaged scholarship research contributes to practice by providing recommendations on how to better manage ERP project deescalation. It contributes to theory by providing a nuanced understanding of ERP project deescalation through project team members' sensemaking activities. [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.]