Cos F1 to H4 When can drop class maintain legally

I’m on F-1 studying in graduate school, I just send out application for change to H-4 visa last week. I want to drop a class(deadline is coming up shortly), but I cannot drop now beacuse it will affect my F-1 status. When I can I safely drop a class meaning I’m not longer need to follow regulations of F-1 student?