graphic user interface design: are there services that allow you to easily update or degrade?

I noticed that in many different types of products and services offered by some different subscription plans, updating is easy. The degradation, on the other hand, is a bit discrete. In most of them, you should contact the help desk to degrade or cancel your plan.

While this is a business decision, are there other negative effects if we allow users to easily degrade a plan? Or make canceling a plan less hidden?

And this may be uncommon, but what happens if a user decides to update / lower / then update again within a period of, for example, one hour? In general, will that cause billing problems?