Buggy workflow:
1) Brent submits diff -> diff status is "Needs Review"
2) Evan approves diff -> diff status changes to "Approved"
3) Brent requests review -> diff status changes to "Needs Review"
4) Brent updates diff -> diff status changes back to "Accepted".
Seems like step 4 should keep the diff status as "Needs Review", as requesting a review should unaccept the diff until another user explicitly approves it again.