you must ENSURE that you have Wi-fi connection, and should probably test 
this with a pokemon you don't like first. 



Step 1 
Go to to the Global Trading Station (GTS). And Log in. 

Step 2 
Once your in the main menu of the Global Trading Station. Go to "Deposit". Put in the pokemon you want to clone. 

Step 3 
Deposit the pokemon into the GTS, make sure you offer it 
for a Pokemon that nobody would trade for it. Cause if someone trades for the 
pokemon in the GTS, Then the whole process is ruined. 

Step 4 
This is the hard part. It should even be considered as the main step 
into duplicating your Pokemon. 

After depositing your Pokemon It will now say: "Checking GTS's Status...." 
On the right of that message, a clock should be going around. On the eighth 
spin, simply turn the DS off. 

It doesn't have to be exactly 8 spins! 
Your goal is to shut your DS OFF 1 spot before the loading is complete. 

Step 5 
Turn your game on. You should get a error message: 
"Your file has been corrupted. The previous file will be loaded" 

Don't worry. This is normal. 

Step 6 
Go back into the GTS, and you should have one in your Party, and GTS slot. 

Step 7 
Logout and save.