re: does your company still offer a pension?

What happens when the company cuts a pension. Is that only effective for current employees (as in if you are still working, you are now on your own for retirement at the drop of a hat), or does it screw over those who are already retired as well? I know my moms company dropped their pension years ago, so she had time to build a 401k. Always seemed much riskier than playing the market in a 401k to me.