A business analyst (BA) is working on a complex project involving many stakeholders for which...

A business analyst (BA) is working on a complex project involving many stakeholders for which the business case has been previously completed and signed off. After an organizational restructure, new stakeholders have been assigned to the project working group, but do not see the value in the project outcomes and refuse to collaborate. What is a guideline or tool the BA can use to focus stakeholders on a common goal?