Forgot to add the code, here it comes (I tried delete and then the update):
function my_acf_save_post($post_id) {
if (get_field(‘are_we_counting_participants’, $post_id)) {
// value is true
// do nothing, value is set to the default or something new was entered
} else {
// value is false
// you can do one of the following
// set field b to a default value
update_field(‘number_of_participants’, NULL, $post_id);
// or delete the value of the field
// delete_field(‘number_of_participants’, $post_id);
}
}
add_action(‘acf/save_post’, ‘my_acf_save_post’, 20);
