alertify notification

Hello; I have opencart 1564 with custom theme; the theme have Newslettre module, but it use the alert of navigator to display the error, success and confirm, for this I have whant to chage the navigator alert by the alertify notification, it work for the success and error message but the problem is with the confirm, because the module of newslettre ask the client the unsubrition if the email found in database. for this I want a help to fix the confirm message.