> ## Documentation Index
> Fetch the complete documentation index at: https://docs.treasuryprime.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Notices of Change (NOCs)

# Notices of Change (NOCs)

A Notice of Change (NOC) is a notification from the receiving bank indicating that information on an originated ACH needs to be corrected. The original transaction still processes — the NOC is a signal to update your records for future transactions.

When Treasury Prime receives a NOC for an originated ACH, the following fields are populated on the ACH object:

| Field                | Type   | Description                                                                                                       |
| -------------------- | ------ | ----------------------------------------------------------------------------------------------------------------- |
| `noc_change_code`    | string | If a notice of change has been received for this ACH, this will contain the latest change code for this entry.    |
| `noc_corrected_data` | string | If a notice of change has been received for this ACH, this will contain the latest corrected data for this entry. |

## Important: Only the Latest NOC Is displayed

If an ACH receives more than one NOC, the `noc_change_code` and `noc_corrected_data` fields are **overwritten** with the most recent values. Previous NOC data is not retained on the ACH object.

## Common Change Codes

| Code | Description                                                 |
| ---- | ----------------------------------------------------------- |
| C01  | Incorrect Account Number                                    |
| C02  | Incorrect Routing Number                                    |
| C03  | Incorrect Routing Number & Account Number                   |
| C04  | Incorrect Account Name                                      |
| C05  | Incorrect Transaction Code (e.g., checking vs. savings)     |
| C06  | Incorrect Account Number & Transaction Code                 |
| C07  | Incorrect Routing Number, Account Number & Transaction Code |

## Webhooks

When a NOC is received, the `ach.update` webhook fires. Subscribe to this event to be notified of changes and take corrective action.

## Recommended Handling

1. Subscribe to the `ach.update` webhook.
2. When an update is received, check `noc_change_code` and `noc_corrected_data`.
3. Update the corresponding counterparty record with the corrected information.
4. Per NACHA rules, corrections must be applied within **6 banking days** of receipt or before initiating another ACH to the same account — whichever is later.

> **Note:** Do not re-send the original transaction. A NOC means the payment was already processed successfully.