Force the Paid Memberships Pro expiration script to run immediately.

pmpro_cron_expire_memberships_now.php

/*
  Force the PMPro expiration script to run immediately.
  
  Add this code into a custom plugin, then login as an admin and visit /?expirenow=1
*/
function pmpro_cron_expire_memberships_now() {
  if(!empty($_REQUEST['expirenow']) && current_user_can('manage_options')) {
    echo "Forcing expirations now<hr />";
    pmpro_cron_expire_memberships();
    exit;
  }
}
add_action('init', 'pmpro_cron_expire_memberships_now');