How to Delete the Polyjuice Potion Level on LEGO Harry Potter for Nintendo DS

Insert your "LEGO Harry Potter" game card into the game slot on your Action Replay DS device. Insert your Action Replay DS device into the game slot on your Nintendo DS.

Turn on your DS. Select the "Code Select" button in the Action Replay main menu to open a list of games. Select the "LEGO Harry Potter" option from the game list.

Select the "New Code" option in the next menu to enter the Code Name screen. Enter the words "Master Code" in the text box, then select the "OK" option to continue to the Code Entry screen. Enter the following code in the text box:
BLHE-36AB8FCA
Select the "OK" option to return to the Code Select screen.

Select the "New Code" option in the next menu to reenter the Code Name screen. Enter the words "All Movies, Chapters and Levels" in the text box, then select the "OK" option to continue to the Code Entry screen. Enter the following code in the text box:
94000130 fffb0000
621620e4 00000000
02146c1c ffffffff
d5000000 000000ff
c0000000 00000021
d8000000 02146be2
d2000000 00000000
Select the "OK" option to return to the Code Select screen.

Check the boxes next to "Master Code" and "All Movies, Chapters and Levels" in the Code Select screen. Press the "Start" button to begin playing the game.

Press the "Select" button once you enter the main playing area. You now have access to all levels, eliminating the need to ever play the Polyjuice Potion level.