Announcements are messages from a DJ to their FANs.
To edit an announcement, go to your profile, then press on your current announcement next to the megaphone icon. Then, press "..." in the top right corner and select whether you want to Delete, Edit, or create a new announcement. Creating a new announcement will remove your old one.
Your FANs will receive a notification only when you first create an announcement and not when you edit an announcement.