ok i got it
`function my_function( $post_id ) {
$postdate = date( ‘Y-m-d H:i:s’, strtotime( current_time( ‘mysql’ ) ) );
$my_args = array(
‘ID’ => $post_id,
‘post_date’ => $postdate );
if ( ! wp_is_post_revision( $post_id ) ){
remove_action(‘save_post’, ‘my_function’);
wp_update_post( $my_args );
add_action(‘save_post’, ‘my_function’); } }
add_action(‘save_post’, ‘my_function’);