My experience is that the operator records the release, but they don't jump on it. I have requested several releases and gotten them, and in one case, I sent a registered letter to the operator which stated the term of the lease was expired, and no production was ongoing, so I would consider the lease null and void unless I heard back from them within 30 days. Sounds of crickets in the silence, but i sent a copy of that letter to the potential new lessee, and they accepted it.