When you first set up parental controls, you were instructed to choose a PIN that would be easy to remember (but not easy enough for a kid to guess). If, however, you need to change the parental settings on your Nintendo 3DS and you discover you've forgotten your PIN, don't panic. You can reset your PIN.
First, you can try recovering it. When you're prompted for your PIN in the Parental Controls menu, tap the option on the bottom screen that says "I Forgot."
You'll be instructed to enter the secret answer to the question you were asked to set up along with your PIN (for example, "What was your first pet's name?" or, "What is your favorite sports team?"). Once you enter the correct answer to your question, you'll be able to change your PIN.
If you forgot both your PIN and the answer to your secret question, tap the "I Forgot" option at the bottom of the input for the secret question. You will be provided with an "Inquiry Number" that you must enter at Nintendo's Customer Service site.
When your Inquiry Number is entered correctly on Nintendo's Customer Service site, you'll be given the option to join a live chat with Customer Service, or you can call Nintendo's Technical Support hotline at 1-800-255-3700. You will need your Inquiry Number to obtain a master password key from the representative on the telephone.
Before obtaining your Inquiry Number, make sure the date on your Nintendo 3DS is set correctly. The Inquiry Number must be used on the same day it's obtained, otherwise Nintendo's representatives may not be able to help you get a master password key.