Q. How do I kill a process called inetd or foo and restart the same so that configuration file get updated?

A. Both UNIX and Linux supports POSIX reliable signals and POSIX real-time signals. Each signal has a current disposition, which determines how the process behaves when it is delivered the signal.

Generally following command is used
kill -1 process-pid

First get pid of inetd:
ps -e | grep inetd
Now force read inetd.conf:
kill -1 xinetd-pid

You can also use pkill command used to send signals. The pkill command allows the use of extended regular expression patterns and other matching criteria.
pkill -HUP process-name

Make syslog reread its configuration file
# pkill -HUP syslogd

Make xinetd reread its configuration file
# pkill -HUP inetd