You can change the elevation of a line you previously digitized.

Change the elevation of each point on a line manually, by a factor, or to a single elevation using Single El. Change the elevations of multiple lines at one time using Multi El. You select the lines to change by drawing a selection line that crosses all the lines you want to change. The first line crossed is changed to the start elevation, each additional line crossed is changed by the increment specified. For example, if you set the Start Elevation to 450, the Increment to 10 and cross three lines with the selection line, ProContractor changes the first line's elevation to 450, the second line's elevation to 460, and the third line's elevation to 470.