Yes, you can. But it is important to note that doing so changes the rule anywhere it applies, so amendments must be made cautiously.
To amend a product rule, navigate to the product, and click on the ‘Rules’ sub-page header.
You can now make amendments to the conditions and actions of the product.
The audit tab keeps a log of changes that occur. You can see which user made a change and when. Click on ‘view’ for a (JSON) breakdown of what was changed.