Wordpress - Remove parent theme action in child

For removing an action hook you should use the same action name, callback name and the priority that was used to add a action in parent theme. And register it on init

add_action( 'init', 'remove_my_action');
function remove_my_action() {
     remove_action( 'woocommerce_before_shop_loop','storefront_sorting_wrapper',9 );
}

Read about remove_action

@Sumit is right, but if you call your function remove_action() Wordpress will throw an error. So this will work:

add_action( 'init', 'remove_actions_parent_theme');

function remove_actions_parent_theme() {
     remove_action( 'storefront_header','storefront_skip_links',0 );
};