update all nodes with roslyn?

gistfile1.cs

                //other junk
                ....
                ....
                Dictionary<StatementSyntax,StatementSyntax> lookup = new Dictionary<StatementSyntax,StatementSyntax>();
                if (returnActions.Count > 0)
                {
                    foreach(var ifStatement in returnActions)
                    {
                        var mainCall = ifStatement.GetPrevious() as ExpressionStatementSyntax;                        
                        var newIfStatement = ifStatement.WithCondition(mainCall.Expression.WithoutTrivia());

                        lookup[mainCall] = null;
                        lookup[ifStatement] = newIfStatement;
                        
                    }

                    root = root.ReplaceNodes(lookup.Keys, (s, d) => lookup[s]);
                }
            }

            return root.ToFullString();