Prior month in renaming

Total newbie. I get the custom date options and have used successfully in some rules. Is there a way in renaming a file that I can get Hazel to put in the year-(PRIOR month)? I'd like this to happen with my monthly credit card/bank statements which, of course, aren't available until the current month for the past month. I've tried doing the 'contents' contains and searching on a date but can't figure out how to get it to focus on the statement's ending date. Thanks, appreciate it.

If there are multiple dates, you can either use surrounding context (text coming before or after the date) or use the "occurrence" selector to select which one to use.

Alternatively, if you grab a date that is a month ahead, when you drop it into your Rename pattern, you can click on it and make a date adjustment (like month - 1).

Thank you, Mr. Noodle! After "noodling" around, I see that adjustment option. Perhaps a case of: "The obscure we see immediately, the obvious takes a little longer." (A.N. Whitehead)
Appreciate your help.