Solved Admin to player toggle

As an admin, the name appears in different color when chatting.
I remember a long time ago there was a plugin that could let an admin transfer between admin or normal player with a command, and while an admin is in normal player mode, the name in chat and other things would be just like a normal player so there would be no way anyone could tell that person is an admin.
Is that plugin still exist? Or is there another one?