Accounting Period Typo - year typed incorrectly in the "To" date

The "To" date was typed incorrectly when creating the Jan 2013 in our calendar. This period has not yet been used.  How can we correct the "To" date from 31-Jan-2031 to 31-Jan-2013?  Getting a field protected against update and the bottom of the screen, as well as the following message: APP-SQLGL-08044:  You can only modify periods that have never been used.   Unable to modify or delete the record.  We have verified there has been nothing entered or posted to that period.  Please advise as to our options.  Thanks!