Usage patterns
〈物〉を逆さにするto turn something upside down
I turned the cup upside down to drain the water.
〈物〉が逆さになるfor something to end up upside down
The photo was hung upside down.
逆さに読むto read something backwards
If you read that word backwards, it takes on a different meaning.
逆さに立てるto stand something upside down
I stood the umbrella upside down to dry it.