cPanel gives you the ability to control and modify SpamAssassin from within cPanel
To do this, login to cPanel, go to the Email section and use the Spam Filters icon.
Once in the spam filtering you will see the following options.
This filtering system works on a Spam Score ( using a numerical basis), so the lower the number, the stricter the filter, the higher the number the more lenient it is.
There are several features in here that you choose here, from the number mentioned above, have spam go to a Spambox, etc.
You can get full details of this function and the settings that could be used by going HERE .