Can I get notified when a flag changes on a contact?

HI folks,

I would like to know how can we get notified via email when a certain flag on Contact changes.

A contact has Deactivated his account. We want to receive an email who has deactivated to an Email address that we provide.

can you please let me know if I can use Series. I tried to use series but in the entry rules it is setting the audience or recipients to that flag with a value in it.

Can someone please help regarding the same.