• Click on the name of the list that has the Sign Up Form
• Click "Edit List"
• You will get an "Edit Email List" pop-up box.
• Uncheck the "Allow people to sign up for this list box " and click Save.

This step changes your list from a Public List to a Private List. A list has to be Public in order to have an active Sign Up link assigned to it.

Because the Sign Up link is still live (meaning someone can click on it) you'll want to edit the Sign Up form.

To Edit the Sign Up Form:

Click on "Contacts"

Put a check mark next to the Sign up form (the name of the Sign up form should now appear in red) and click Edit . Then change the text of the Sign Up form to say that this Sign Up form is no longer available (and provide them with an alternative way to reach you , if you want.)

Or remove the sign up link or form from your website, Facebook, where ever you added it.

If you change your mind and want to allow people to sign up for your list click on Messages > the name of the list > Edit.  Then recheck the box that says "Allow people to sign up for this list box" and click Save.