What does the 'unlink' button do in a workflow Email Action?

By default, autoresponders are created with an email that is linked to a global system template. A linked email is uneditable as the email is referencing a template. The idea of linking to a template is all changes to an email that appears in various places should be managed in one place (Email Library). Global templates are unediable, but you can create your own versions of the global templates by unlinking a linked email,. Unlinking a template allows you to edit the email. Typically you want all of your autoresponders to link to the same template, thus if you change the template, it changes all of the autresponders.

To create your own autoresponder template:

1. In an autresponder, unlink the autoresponder email from the global template. 
2. Edit the Autoresponder
3. Click the 'save to library' button at the top of the edited email (save it as Email Prospect Autoresponder)
4. Exit the editor back into the workflow view
5. delete the Email Prospect action item
6. Drag a new Email Prospect action item from the actions toolbar
7. Click the action, click the 'New Email button' on the slider
8. Choose the recently saved Email Prospect Autoresponder template from the account templates
9. Choose 'link'

Every autoresponder starts as a linked email to the global template. Every form/landing page you create you will have to go in and delete the default, drag a new 'Email Prospect' action, and select your new template, and link to the template. Linking ensures that, once you have multiple landing pages/forms, all changes are done in one place (the Email Library).