Ah ok that helps. I thought that auto-close meant auto-settle in ca$h. They actually deliver the shares.
It's not like oil or gold; no, they will not drive up to your house with an armored truck with bullion or tanker with oil.
I'm still not sure if I can let an ITM option expire--with neither cash settlement nor execution. Just let it die; no payment, no shares.
As others have pointed out: yes, it's possible; no, we can't tell you how, you have to call your broker; and don't do it for tax reasons, because that's misunderstanding tax law.