You may need a time dimension (it's a bit of a modellers choice, and I'd probably err with just storing the time as part of the fact).

I would also suggest you would need a status dimension. It's probably fairly small and could form a part of a generalised "status" dimension across multiple facts.

You may also need two fact tables: one for tracking who worked on it and one for tracking when it changes state. Again, it's a modellers choice, but I find in practice those are two very different things for reporting purposes, so often it's a good idea to model them separately and make the subsequent reporting easier.

Some ideas anyway; I can't suggest more without seeing more of the data mix and the reporting requirements.