Here are some screen shots of the process.
First you have to go to Null and speak to Trixie.

Scroll down and click, as indicated.

You will see this box of text. Click ok.

Adjust the slider bar to the level you desire and hit "apply."

As you can see here, I've lowered my MAX ring CL to 3.7.

NOTE. This feature lowers the max CL of your rings. So, say you have 4 CL10 rings and 4 CL1 rings on and you lower it to CL5, you'll have 4 CL5 rings and 4 CL1 rings. This will leave you a total CL around 3-4
You're all done, now go and have fun!
Happy Farming!
*To return your CL to it's normal level, just repeat the process. *