# Historical Corrections

> Learn how to create historical corrections for signed-off pay periods.

Historical corrections are required when modifying a resource in a closed pay period,
or which may impact a closed pay period. This safety mechanism ensures that changes to
historical data are intentional and properly documented for payroll and audit purposes.

## When Historical Corrections Are Required

Some examples of when a historical correction is required include:

-   Creating, updating, or deleting timecard punches in signed-off pay periods
-   Modifying shifts in signed-off pay periods
-   Updating pay codes or other pay-related system configuration in the past

## Historical Correction Structure

To make a historical correction, include the `historicalCorrection` object in your request body:

```json Historical Correction Structure icon=braces
{
    // Your normal request data
    "startTime": "2024-01-15T08:00:00Z",
    "endTime": "2024-01-15T17:00:00Z",

    // Historical correction acknowledgment
    "historicalCorrection": {
        "note": "Correcting missed punch from employee timesheet review"
    }
}
```

### Fields

<ResponseField name='historicalCorrection' type='object' required>
    Required when modifying historical data that may affect pay.
    <Expandable title='properties'>
        <ResponseField name='note' type='string'>
            An optional note explaining the reason for the historical correction. While
            not required, providing a clear explanation is strongly recommended for audit
            purposes.
        </ResponseField>
    </Expandable>
</ResponseField>

## Error Handling

### Missing Historical Correction

If you attempt to modify historical data without the required acknowledgment:

```json Missing Historical Correction Error icon=braces
{
    "type": "https://developers.untetherlabs.com/errors#missing-historical-correction-acknowledgement",
    "status": 400,
    "title": "A historical correction acknowledgement is required to create a historical correction.",
    "detail": "This action would create one or more historical corrections, but no historical correction acknowledgement was provided."
}
```

You may handle this before sending the request, or as a retry after receiving the error.

For additional help with historical corrections, [contact our support team](mailto:support@untetherlabs.com).