How do I temporarily stop the SpamAssassin spam services, but allow mail to keep flowing?

This would have to be done within the actual email program that you are using. For example, if you were using Postfix, here is what you would do:

Go to /etc/postfix/main.cf. You will see a reference to the smtpd_recipient_restrictions section and it looks at check_client_access cidr:/etc/postfix/cidr_greylist_network_exceptions.

Adding the IP, xxx.xxx.xxx.0/24 OK and reloading Postfix allows mail from that IP through.