[CentOS] smtp mailer or SMART_HOST in sendmail.mc

Is there a EASY way to change the SMART_HOST in sendmail.mc.
Some command line that does it?

Trying to explain to customers editor commands, etc... to
edit this file, change the name, make and service sendmail restart
is BIG for someone that doesnt know linux...

Just wondering if something exists already before I make something.
Dont wish to redo anything.

Thanks,

Jerry