The CHANGE command.
Use it to change the radii of several circles
or
CHANGE a line with ORTHO on to guarantee a true horizontal or vertical line.
or
CHANGE several lines to the same point (with ORTHO on to make parallel lines)
or
Draw several random lines, and a couple of circles. Enter the CHANGE command and select the objects and press enter. When prompted for the change point or properties enter the word DRAG (toggle ORTHO off). You can then change the elements one at a time. To swap ends of lines that are being changed, move the crosshair such the the "dragged" line would be 0 length, and the anchored end will switch.