Currently, you have to
/announcement end -> /announcement create in order to make any edits to an existing announcement, which pings everyone and can cause a lot of problems for repeated updates. I know this is already possible using powers™, so hopefully it wouldn't cause too much trouble too implement. I am not concerned with the possibility of users missing out on information if they aren't pinged for an update, because if that's the case then staff can just use discretion to fully end -> fully begin the announcement instead.