How do I downgrade iCloud storage?

Thanks Al, That sort of helped... I finally figured out that I had my previous and current iPhone linked to the same account. At first the Downgrade Options bar was not displayed on my current device.

It was only when I erased my previous iPhone from my account that the Downgrade Option bar was displayed, but then it wouldn't respond. I had to call Apple Support to get them to fix it on their end. Now it works just fine.