Well that can be little work as you need to create another widget for it.
Open the inc/widget.php file and add the following code inside circumference_widgets_init() function to create new widget
'name' => __( 'Call to Action 2', 'circumference' ),
'id' => 'cta2',
'description' => __( 'This is a call to action 2 which is normally used to make a message stand out just above the main content.', 'circumference' ),
'before_widget' => '',
'after_widget' => '',
'before_title' => '
'after_title' => '
and create sidebar-cta2.php file and copy the content of sidebar-cta.php file to this file.
In sidebar-cta2.php file, make sure you change the code of dynamic sidebar to :
And put this code wherever you want to display this new call to action block in header.php ( I assumed that you want to add this on header).
Now you can already see Widget placeholder is added Appearance -> Widget area and add the widget.