I believe this is a Physogyra coral (closely related to Plerogyra), and I received it on 8 February 2020 in quite bad condition. Most of the tissue was rotting along the edges, and the skeleton was exposed.
By 9 May 2020, the coral was no longer receding, had polyp expansion, and was starting to regrow over its old skeleton.
Here the coral is fluorescing under actinic lighting.
Only three months later, and this Physogyra was well on its way to full recovery!