Plugin Customization: Disabling choices of button design on Siteorigin Button Widget

Hi,

I would like to disable the choice of ‘atom’ and ‘ wire’ of button them on Siteorigin Button Widget.
I know I can directly modify the plugin code of so-widgets/widgets/button/button.php like below.

However, once the plugin is updated later, I need to re-modify them again.
Is there any better way to keep the modification even update happening?

Thank you and best regards,
Hideto

****** button.php ******
function get_widget_form() {
return array(

.
.
.

‘theme’ => array(
‘type’ => ‘select’,
‘label’ => __(‘Button theme’, ‘so-widgets-bundle’),
‘default’ => ‘atom’,
‘options’ => array(
//’atom’ => __(‘Atom’, ‘so-widgets-bundle’),
‘flat’ => __(‘Flat’, ‘so-widgets-bundle’),
//’wire’ => __(‘Wire’, ‘so-widgets-bundle’),
),
),

.
.
.

}
******************