No, there's currently no way to delete a disposition that's already been recorded against a specific call in Genius.

This is intentional - dispositions are part of the call record, and removing them after the fact would undermine that history.

If you no longer want to collect a particular disposition going forward, you can remove that disposition question entirely from your Company or Team settings. Note that doing so means you'll stop collecting that after-call information going forward - it only affects future calls, not past ones.