I recently have been working on dynamically changing an entity that was originally setup as organization owned to be team owned.
After pulling my hair out trying various methods that would allow me to keep the data intact, I decided to export the data and empty out the entity so I can update it. This method allows me not to drop the entity and use the method from my earlier post.
However, the relationships are set up as referential and that won't work for what I want since there are child records related. The way I got around this was to setup those relationships as Configure Cascade. I then selected the Remove Link action in the Delete picklist.