sendmail not appearing to ps

I am having trouble finding the process, or subsystem, sendmail running on our client's server. They are runnning AIX version 5.3.9.0. When I run "ps -ef | grep sendmail" I only get my current ps process as a match. Running "ps -ef | more" and wading through the results also does not show sendmail as running.

Ultimately what I attempting to do is restart the sendmail service by running "refresh -s sendmail" but that tells me:

0513-036 The request could not be passed to the sendmail subsystem.
Start the subsystem and try your command again.

I have confirmed that sendmail is indeed running by using it to send mail.

I'm not an expert in UNIX or any of its flavours by any means so I thought I would put it out there for advice and guidance.

2 things to note here: the mailer daemon doesn't have to run all the time unless the machine is configured to also receive mail from other machines. And the sendmail command itself has been copied over (at least by name) to other mailer daemons (eg. Postfix) since it's become somewhat of a general command for sending mails.

Check which, if any, mailer daemon is installed first.

How do I know if another mailer daemon is running?