Update-proof way to modify the form template?

As the title says, I’d like to modify the form template.

I found the template ‘wp-content/plugins/buddy-registration-widget/templates/form-template.php’ and updated it, but it will probably get overwritten in the future.

I’ve temporarily disabled the updates for this plugin, but having customization not disappear would be great.

best regards

NOTE: to anyone who’d need info, here’s how I disabled the plugin update
https://stackoverflow.com/questions/17897044/wordpress-how-to-disable-plugin-update/#answer-23769141