FHE operates under asymmetrical encryption and the one running the software needs the public key to perform the FHE operations on the data. The private key is

FHE operates under asymmetrical encryption and the one running the software needs the public key to perform the FHE operations on the data. The private key is known to the manufacturer (although there are some cool applications if no one knows the private key, provably) and is part of the logical circuit of the FHE so that it can decrypt and freshen it's state.