How to adjust the score of spamassassin tests.

==== Required information ====
- iRedMail version: 0.8.5
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: CentOS 6.5
- Related log if you're reporting an issue:
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I'm having trouble finding a way to adjust the scoring of Spamassassin tests, namely RCVD_IN_DNSWL_MED. I'm finding a lot of spam is having this test applied and is lowering the spam score by 2.3. I would like to adjust this or disable it. How do I adjust this test and all other spamassassin tests?

Thanks!
Luke