Options can be overridden using the -o or -O command
line flags. For example,
/usr/lib/sendmail -oT2m
sets the T (timeout) option to two minutes for this run only;
the equivalent line using the long option name is
/usr/lib/sendmail -OTimeout.queuereturn=2m
Some options have security implications. sendmail(1M) allows you to set these, but relinquishes its setuid root permissions thereafter. For example, it sets its effective UID to the real UID; thus, if you are executing as root, as from root's crontab file or during system startup the root permissions will still be honored.