Help: how to add a change issue if milestone's status has changed

[zdway10]

Ref "Example of creating subtask if the issue's status has changed," I want to add a change issue if milestone's status has changed except for milestone's status change to "done" or "resolved", how to realize it?
mark: change issue is define in the redmine.xx.com/trackers and id is /trackers/5/

---

Example of creating subtask if the issue's status has changed
Fill the "before save" script with:

@need_create = status_id_changed? && !new_record?
Fill the "after save" script with:

if @need_create
issue = Issue.new(
author: User.current,
project: project,
tracker: tracker,
assigned_to: author,
parent_issue_id: id,
subject: 'Subtask',
description: 'Description')
issue.save!
end