You can request cross-save deactivation from Bungie, using the form at the bottom of the page in [url=https://www.bungie.net/en/Help/Troubleshoot?oid=48099]this article[/url]. If your request is granted, you would not need to wait the full 90 days for deactivation. Bungie handles the requests during normal business hours Pacific Time and in order received. Once deactivated, you can unlink the incorrect account and link the correct one. After waiting out the 90-day security lockout, you can reactivate cross-save with the right setup.