LOST APPLE ID PASSWORD CAN'T CONTACT OWNER

I bought a phone off of a person a while back and now I need to restore my phone back to factory settings, but when I try to, the phone is set up under an icloud/find my iphone setup, and it asks for this persons apple id, and i can't get ahold of the person to get the password so I can turn this feature off so I can restore, is there any way that I could bypass this?