Passive Subwoofer How Do I Connect My New Receiver To My Old One To Power My Passive Subwoofer?

How do I connect my new receiver to my old one to power my passive subwoofer? - passive subwoofer

I have a new Sony STR-DG720 receiver. I already have a home theater, the Sony DAV-HDX275. The new receiver has an RCA output for an active subwoofer. The subcommittee that I have is passive. How do I get my son new receiver to my old passive subwoofer power?