My shower drain is epoxied, what do I do to get the drain out?

My prefab shower drain that screws in is glued with epoxy that was used to put the tile down. I’ve had to remove the tile and now the drain is stuck. How can I get the drain to screw down without ruining it?

The person who tiled my shower put the tile under the drain so the drain sat on top of the tile. It couldn’t drain all the water. Now I have to re-tile it, but regular mortar or mastic will not stick to the shower base (RediTile brand), so an epoxy that came with the base was used.