Complex sentence: Conversely, a form of "ex post facto" law commonly called an "amnesty law" may decriminalize certain acts or alleviate possible punishments (for example by replacing the death sentence with lifelong imprisonment) retroactively.
Split into simpler sentences: Conversely, a form of "ex post facto" law commonly called an "amnesty law" may decriminalize certain acts. Other legal changes may alleviate possible punishments (for example by replacing the death sentence with lifelong imprisonment) retroactively.