How to transform block variant to default version?

I have a simple block variation:

  wp.blocks.registerBlockVariation(
    'core/heading',
    {
      name: 'headline',
      title: __('Big title'),
      attributes: {
        className: 'headline'
      },
    },
  );

And I want to be able to transform from this variant to standard core/heading and back. How to achieve this? Tried to get it from Handbook, but with no success.

Thanks a lot in advance!