Change diameter of Circle at once.
 
  Program name : CRC.LSP

You don't use it often, but sometimes you need to change the size of all (or some) circles in your drawing. With this program, 
You can selects all the circles or a specific size circle and converts it to the desired size.

 
  Example
Radius/All/<Select>:   [Radius : You can select circles that has specific radius
                                  A : All circle in drawing is selected
                                    : You can select circle that you want to select]
Select circle:
Select objects: {p1}            [Pick start point of window box]
Other corner: {p2}              [Pick end point of window box]
3 found
Select objects:                [Finish selecting]
3 found
Enter New Radius: 500  [Enter new radius]
3 Modified