To disassociate one or more messages from a rule, right-click on the message(s) in the Rule Enforcement Messages panel under the Rule Configuration panel, and choose either Remove selected or Disable selected. These actions have the same effect as deselecting the message(s) using the Rule Enforcement Messages dialog , although Disable selected will leave the message(s) visible on the panel, albeit in a dimmed state, so that you can quickly re-enable the message(s) (by choosing Enable selected from the same right-click menu).
Selecting the Remove All Messages option disassociates all messages from a rule, and simultaneously removes the messages from the Rule Enforcement Messages panel.
Do not forget to click Save to keep your changes.