Aside from modifying your command thru PGP files which I already discussed it here, and here on where you can find it, and how you can modify it. There is also another way of modifying your AutoCAD command that is thru Command Alias Editor, which you can find under the Express menu, and under Tools. And from the command prompt type ALIASEDIT.

After key-ing in the command ALIASEDIT, dialogoue box will pop-up, and you are now ready to edit the command you desire to change according to your taste.

Command Alias Editor, behave like the traditional PGP files, they only differ on how to acces them and their interface, which you can see that ALIASEDIT has a dialogue box which you can modiy it easily, whereis you can modify the PGP only on notepad.