While running the SKETCH command, with
the pen up or down, enter e (Erase).
If
the pen was down, it moves up.
Move the cursor to
the end of the line you drew last and then move it back as far along
the line as you want to erase.
To end the erasure
and return to the SKETCH Command prompt, enter p. To
undo the erasure, enter e.
If
you want to change the current viewport while sketching, make sure
the pen is up, all lines entered so far have been recorded, and
Tablet mode is off.