Things You'll Need
Instructions
Go into the Pokemon storage system by walking up to a PC in any PokeCenter and pressing A. Choose "Someone's PC" from the list of options to bring up the Pokemon storage menu.
Choose "deposit Pokemon" from the menu at the right hand side of the screen. Select the bad egg from your party and deposit it into box number one. Use the move option to move the bad egg into the first slot in the first box.
Save the game by entering the pause menu and choosing "save game."
Insert the Pokemon Diamond DS game into the action replay DS cartridge before placing the cart into your Nintendo DS. You should hear a click to indicate that it is properly inserted.
Turn on your Nintendo DS and you will be faced with the action replay screen.
Press the star symbol on the bottom screen then choose "add new code" from the top screen.
Enter the code. When prompted, type the following code into the code field: 923FFFA8 00002400, B21C4D28 00000000, B0000004 00000000, 0000C370 00000000, 0000C374 00000000,1000C378 00000000.
Name your code "Box One Slot One Delete" or something else that will remind you what it does before selecting it to activate the code.
Press the start option on the bottom screen to launch Pokemon Diamond with the code enabled. When you view the Pokemon storage system you will see that the bad egg will have been deleted.