A pin number is issued to the consumer when he chooses to put a security freeze on his credit report. This number is required to unfreeze or thaw of frozen credit report. This number is a way to ensure that it is the consumer itself and not some identity thief that is trying to remove the security freeze from the credit report. In case you have misplaced the pin number you will need to get in touch with the credit bureau and apprise them of the situation. Very often this process can be done online through the website of the credit bureau. You can proceed with requesting the reissue of a pin number by visiting the security freeze section of the website of the National credit bureaus. In almost all the cases you will be required to send in a written request through postal mail along with certain documents that will be required to prove your identity and verify request as coming from legitimate quarters.