To Change a Hole Type

Select the Modify Parametric Solid or Feature tool.
Select the countersunk hole.
Accept to open the Edit Hole dialog.
Change Hole Type to Counterbore.
Make other adjustments as required.
Click OK.
The solid is regenerated with the hole changed to a counterbore type.

Left: The original countersunk hole. | Right: After modification to a counterbore hole.