u/Elludrilinho

I want to repair my rain shower head, but I'm having trouble separating the part where the screw thread is located from the pipe. Theoretically, it should be attached with a screw, but on the photo you can see that there's no screw, so it must be attached another way. I've tried unscrewing it, but it won't release. I asked the landlord how it was installed, but she doesn't know. I tried to fix it with mounting tape, but unfortunately, the glue won't grip the metal part. Any ideas on how else I could fix it?