Wikipedia:CLEANSTART

A clean or fresh start is when a user stops using an old account in order to start afresh with a new account. The two most common reasons for wanting a clean start is recognizing past mistakes, and to avoid harassment. The old account must be clearly discontinued, and the new account must avoid editing patterns or behaviors that would allow other users to recognize and identify the account. It is expected that the new account will be a true "fresh start", will edit in new areas and avoid old disputes, and will follow community norms of behavior.

A genuine clean start is not considered improper. However, if an editor uses their new account to resume editing articles or topics in the same manner that resulted in harassment or a negative reputation in the first place (becoming involved in disputes, edit warring or other forms of disruptive editing), the editor will probably be recognized and connected to the old account. Changing accounts to avoid the consequences of past bad behaviors is usually seen as evading scrutiny and may lead to additional sanctions. Whether a new account is a legitimate fresh start or a prohibited attempt to evade scrutiny is determined by the behavior of the new account. A clean start is not permitted if there are active bans, blocks or sanctions (including, but not limited to those listed here) in place against the old account.

If you decide to make a fresh start and do not wish to be connected to a previous account, simply stop using the old account and create a new one that becomes the only account you use. To reduce the chance of misunderstandings, you should note on the user page of the old account (while logged in under that account) that it is inactive, by using the {{}} tag or leaving some other message. You may not use more than one account at a time.

If you are not under Arbitration Committee sanctions, you are not required to notify anyone of your clean start. However, you may find it helpful to notify the Committee or a member of the functionaries team, and get confirmation that there are no obvious problems with you following the clean start procedure. This may reduce the risk of misunderstandings that might result from "behind-the-scenes" discussions and investigations, and may assist you in an appeal of a mistaken block or sanction for creating an alternative account.

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Wikipedia