I don't see why you couldn't cut it vertically, into 2 or more usable pieces,
But I don't know if they will grow out. I've never really had anything but slow, steady decline from these and Gorgonians.
From the pic it looks like algea is on it and that is always the problem with them. That's also the root of the decline. I've never had one last more than a year. I would put it in moderate-high flow, if possible, and most are non-photosynthetic. Good luck!