These features makes it possible to both add and remove secondary axes in Corporate Charts. Note that these features are only available in Excel.
Add a secondary axis
First, select the chart you wish to add a secondary axis to.
Click the icon in your "Specific Chart Elements" section. This opens a dropdown menu.
Press "Add Visual Secondary Y Axis" for adding a Y axis to your chart.
Remove a secondary axis
Select the chart you wish to remove a secondary axis from, and open the same dropdown menu from before. Click "Remove Secondary Y Axis"