As already mentioned in other answers you can't edit object parameters after they are created in Blender. After the creation process they become regular mesh objects and loose any "parametric properties" they had.
In an attempt to not leave you empty handed I'll try to present an alternative solution: Be smart, use available tools to your advantage.
Here is a "Parametric Sphere" made from a single vertex meh and two screw modifiers.
You could even control radius with an additional Displace Modifier"
If you foresee the need to adjust geometry after the fact, or edit parameters frequently, be smart about it build your objects in a way that allows tweaking them easily.
This is where Modifiers come in.
If you need to, say, easily change the number segments of a cylinder, or regularly change its height then it would be smart to instead of adding a cylinder modifiers instead.
Create a simple single edge mesh with no actual faces, add a Screw Modifier to it, then a Solidify Modifier. You now have a "Parametric Cylinder" you can easily adjust the number of segments and height of.
This is what is often called a "non-destructive workflow", where modifiers are kept "live" so they can be easily edited.
This will obviously not work every time or for everything, and you can't always achieve every end result without some destructive steps, but be creative about it.
Use modifiers to your advantage, extend this to other tools like constrains, drivers, shapekyes etc., and you can go a long way in creating easily editable "parametric objects".