How do I reset Notification Setting from backend for all users?

Hi Team,

I have just tweak the notification setting from the back-end and I would like to re-apply my latest settings to all site users. How can I do that? I know I can reset user's privacy but cannot find a way for resetting notifications. Please advise.

p.s. Since I want to disable almost all my Email notification (except 1-2 items) for my site to avoid creating too many spam mails. Thanks.

Best regards,
Alfred/ Dreamonde