Way to delete level instances from World Partition

Hello everyone.

I have a question about how level instances work inside World Partition map. I created a level with World Partition and set a few level instances there already. Saved and everything is fine. However these instances were for learning purposes and now, since I am iterating further - I wanted to delete them from my World Partition map.

Now the issue occured, once I delete a level instance actor from WP map, there is nothing to save etc. And once I reload the map, this actor is still there. I tried to break the instance and delete meshes but that didn’t work either.

Do you have any tips? Did you find this problem as well?