I have read a number of posts on SE.com regarding cronjobs, crontab, and how to reschedule cron jobs. But it seems that, in my Debian environment, a session cleanup job schedule simply called "php", that is present in /etc/cron.d, specifying root as the user, and currently running every 30 minutes, cannot be rescheduled, unless a reboot occurs.
9,39 8-20 * * * root [ -x /usr/lib/php/sessionclean ] && if [ ! -d /run/systemd/system ]; then /usr/lib/php/sessionclean 2>>/dev/null; fi
Whatever hour/minute changes I do will not be taken into account, despite /etc/init.d/cron restart . It is on a production server, therefore the host can't be restarted easily, or as an experiment.
Is there a command I can issue to tell crond to take into account any rescheduling?