You can edit an existing accounting period provided that the period is not closed or the period end date has not passed. Any changes made to the fiscal year end of an accounting period globally changes the fiscal year end for all the accounting periods from the current date forward.

To edit an accounting period

Navigate to General Ledger > Manage > Accounting Period Dates.
The Accounting Period Dates window opens.

In the Fiscal Accounting Period list, select the accounting period to edit and then click Edit.
The Edit Accounting Period window opens.

If required, change the accounting period to either Monthly or Custom.

If required, change the accounting period End Date.
You cannot change the end date to a date later than the following period’s end date.

If required, change the fiscal year end by clicking Change Fiscal Year End.

Click Save.