By using the action Opt-in contact you can create a rule that will automatically change a contact’s status from opt-out to opt-in.

From then on, that contact will be able to receive messages from the system.

Use: This action can come in handy if you want to try to reach out to customers who never opted in. For example, you can send a reminder to people, who at some point submitted their contact details through a contact form, and still visit the site, but never confirmed their subscription (as per the double opt-in model). As long as you can verify if the opted-out people are still interested in your content, using this action is a fine way to grow your list of subscribers.