Cache not persisted until after action completes

During or shortly after the Release action for a ChangeOrder I would like to perform additional updates to the related Project. However, I am not sure how to do this in a way where the Release action is full persisted before continuing.  

Below I have attempted to handle the standard release action (Base.Release), and then tag on a function call (SetCurrentOrderSet) to update the project, however since the Release action has not been persisted my logic in SetCurrentOrderSet fails.

public class ChangeOrderEntry_Ext : PXGraphExtension<ChangeOrderEntry>
{  
      public PXAction<PMChangeOrder> release;

        [PXUIField(DisplayName = "Release")]
        [PXProcessButton]
        public virtual IEnumerable Release(PXAdapter adapter)
        {
            var result = Base.Release(adapter);              

            PMProject prj = this.Base.Project.Current;

            ProjectEntry prjGraph = PXGraph.CreateInstance<ProjectEntry>();
            ProjectEntry_Extension prjGraph_Ext = prjGraph.GetExtension<ProjectEntry_Extension>();

            prjGraph_Ext.SetCurrentOrderSet(prj);


            return result;
        }
}

I have tried to use the RowPersited event to call SetCurrentOrderSet but am unable to initialize a graph inside the function without error.

How could I better handle this logic?