Oasis Springs Apts Residential Rental broke my Burners and Builders lot. It did not properly function as a residential rental and not I can not change it back. If I do it goes back to being a residnetial rental that can't be bought and can not properly be lived in.
I can think of a couple things you can try.
Try bulldozing the lot and try to change the venue on the vacant lot.
Enter the lot from the map and try replacing it from your Library with another venue type. In your case, a gym but any venue should work. Usually, you will get a popup asking which venue type to assign the new lot.
Try placing a new lot from the map directly on that lot. Again, you should get the venue choice popup. This might take a while compared to doing it on the lot.
Hope this helps.
