Partnership Executive Team

Sonja Bjork, Chief Executive Officer

Sonja is responsible for the development and general management of Partnership. She leads the operations of the health plan and all related programs. Sonja enjoys working with Partnership's Consumer Advisory Committee and is proud of Partnership's work to promote access to care through provider recruitment and workforce development.

Sonja serves as a commissioner on the national Medicaid and CHIP Payment and Access Commission (MACPAC), a non-partisan legislative branch agency that provides policy and data analysis and makes recommendations to Congress, the Secretary of the U.S. Department of Health and Human Service and states on a wide array of issues affecting Medicaid and the State Children’s Health Insurance Program.

Prior to becoming CEO, she served as COO/deputy CEO. Before joining Partnership, Sonja worked as a dependency attorney representing youth in the child welfare system.

Sonja received a juris doctorate from UC Berkeley School of Law and a bachelor's degree in sociology  from University of Wisconsin, Madison.

Wendi Davis, Chief Operating Officer

Wendi is responsible for the oversight of operations and executive management of Partnership regional offices and several departments: Member Services, Claims, Configuration, and Transportation. Wendi provides leadership in organizing our operational teams and interdepartmental communications, and participates in strategic planning in the development of new business lines and programs.

Prior to this role, Wendi served as deputy COO, Northern Region executive director and Northern Region claims director. Previously, Wendi was a Northern California executive director of revenue cycle at Adventist Health System/Cerner Corp. and Northern California director of revenue cycle at Kaiser Permanente and CHW/Dignity.

Wendi received a master's in health care administration from St. Joseph's College of Maine. She has a bachelor's degree in political science and economics from Chico State University.

Dr. Robert Moore, M.D., MPH, Chief Medical Officer

Dr. Robert Moore is responsible for the appropriateness and quality of health care delivered through Partnership. He leads and oversees Partnership’s team of medical directors and keeps staff and providers informed and up to date on changing health regulations and guidance.

Before joining Partnership, Dr. Moore was a chief medical officer at Clinic Ole Community Health and Redwood Community Health Coalition.

Dr. Moore received a doctorate of medicine at UCSF. He has a master’s of public health from Columbia University, a master’s of business administration from Western Governors University, and a bachelor’s degree in biochemistry from UC Berkeley. He completed his family medicine residency at Ventura County Medical Center.

​Patti McFarland, Chief Financial Officer

Patti is responsible for directing the financial activities of Partnership in a manner that anticipates and supports current and future organizational objectives. She is responsible for the day-to-day operations of financial reporting, purchasing, budgeting, financial analysis, and decision support as well as the continuous improvement of these departments. She also oversees administrative services (reception, mailroom, and fulfillment), workplace and facility management, ergonomics, and employee purchasing/acquisition.

Before joining Partnership, Patti served as chief financial officer at two other health plans, CalOptima and Central California Alliance for Health.

Patti received a bachelor of science in accounting from Arizona State University.

​Tina Buop, Chief Information Officer

Tina Buop is responsible for technology strategy and solutions, technical operations, and IT security at Partnership. She leads the IT Department, including applications and AI development, electronic data interchange (EDI), infrastructure operations, data governance, field support, security, and the IT program office. 

Prior to this role, Tina served as the CIO of Pacific Partners Management Services Inc., a division of HCA Healthcare, and in leadership positions with independent physician associations and a federally qualified health center, and as the CEO of a medical startup company. 

Tina received her bachelor’s degree in political science and public administration from California State University, Hayward, and her Project Management Professional certification from the Project Management Institute. Tina enjoys her time with her family, the outdoors, volunteering for a pet rescue, and youth mentoring.

Amy Turnipseed, Chief Strategy & Government Affairs Officer

Amy is responsible for the operations and executive management of the following departments: Regulatory Affairs and Compliance (RAC); Grievance and Appeals; Communications; Legal; Provider Relations; and Operational Excellence/Project Management Office. She also serves as compliance officer, and presents to the Board of Commissioners on compliance issues, including maintenance of the health plan's compliance plan and annual risk analysis.

Before joining Partnership, Amy was a senior consultant at Harbage Consulting, where she served as project manager for California's Coordinated Care Initiative. In this capacity, she supported policy development and execution, and facilitated meetings with state department leaders, advocates and consumers.

Amy received a master's in public administration from the University of Southern California, with an emphasis in political management. She has a bachelor's degree in history and political science from Gonzaga University.

​Katherine Barresi, RN, Chief Health Services Officer

Katherine Barresi is responsible for the overall leadership and strategic direction and management of the programs within the Care Coordination, Population Health Management, Utilization Management, and Health Equity departments at Partnership.

She is also at the forefront of Partnership's implementation of CalAIM (California Advancing and Innovating Medi-Cal), the state's bold initiative to transform Medi-Cal through new and improved services.

Katherine joined Partnership in 2013 and served as the director of Care Coordination and senior director of Health Services before moving into her current role. Katherine is a registered nurse, a licensed public health nurse, board certified nurse executive, and certified case manager. She earned her bachelor of science degree in nursing from Sonoma State University.

​Mark Bontrager, Senior Director of Behavioral Health

Mark is responsible for oversight and management of Partnership activities involving behavioral health (mental health and substance use) services and community projects that support access to and improvement of behavioral health. He also works with Partnership leadership, member counties, providers, and the community to develop the health plan's approach to behavioral health services.

Before moving into his current role, Mark was director of regulatory affairs and program development for Partnership. Prior to coming to Partnership, Mark was executive director of Aldea Children and Family Services. He has also worked as a private practice attorney and held multiple positions at the Villages of Indiana Inc.

Mark received a juris doctorate degree from Indiana University School of Law and a master's of social work from the Indiana University School of Social Work.

​Naomi Gordon, Senior Director of Human Resources

Naomi is responsible for the overall direction of Human Resources and Workforce Development while ensuring efficient operations, compliance with policies and procedures, and achievement of organizational objectives. She provides leadership in the planning and execution of education, training and development programs in support of the overall business plan, and strategic and operational goals.

Naomi started at Partnership in 2006 and rose through the ranks of Human Resources, including serving as manager, associate director, and director of organizational development before becoming senior director. Before Partnership, Naomi worked at L-3 Government Services, where she recruited and supported contractors.

Along with her Partnership duties, Naomi volunteers as an advisor on the general plan advisory committee, Fairfield Forward 2050. She served as board chair on the Learning and Development Synergies Board for Local Health Plans of California.

Naomi has a bachelor of science in business management from the University of Phoenix.