To Modify a Visible Face of a Solid by a Set Distance

Select the Modify Solid Entity tool, with the All icon selected.
Turn on Distance.
In the Distance field, type the desired value.
Select the face to modify.
The face highlights.
Move the pointer to define the direction of the modification.
If Distance is off, the pointer defines both the direction and the distance of the modification.
Accept to modify the solid.

Left: Select a face, then move the pointer to define the direction. | Right: Accept to complete the modification.

Modifying a curved face of a solid. | Left: Select the face, then move the pointer to define the direction. | Right: Accept to complete the modification.