# Reject a vendor bill

Operation ID: `rejectVendorBill`

Group: Accounting › Vendor Bills

[Open in the interactive reference](https://docs.api.lensing.ai/lensing/v1/endpoints/rejectVendorBill)

`POST /accounting/vendor-bills/{id}/reject`

Retry-safe: A write that accepts Idempotency-Key: repeating a request with the same key replays the stored answer instead of executing twice.

Rejects a vendor bill. The rejection goes through your tenant's approval policy. You can send an optional reviewMessage, and the response is the bill's status afterward.

Rejecting doesn't void or delete the bill, and the bill keeps its number and its audit trail. A bill rejected from 'pendingApproval' has no journal entry. Rejecting pending changes to an approved bill undoes the changes, and the bill stays 'approved' with its journal entry.

Whether you may reject the bill depends on your approval policy. When the policy refuses, the request fails with APPROVAL_FAILED, and reason has the policy's message.

## Parameters

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `Api-Version` | header | string · v1 | yes | The API version this request targets, named by its public identifier. Required on every request; omitting it, or naming a version this company does not have, is answered with 400. This document describes version `v1`. |
| `Idempotency-Key` | header | string | no | An opaque caller-chosen string (1-255 characters) that makes this request safe to retry. Repeating the same key with an identical request body replays the original response instead of re-executing - but only once that original request succeeded; a failed attempt re-executes on retry. Repeating the key with a different body is answered with 422. A key still in flight is answered with 409 - as is a key whose original request was interrupted before it finished, for a few minutes afterwards, until that attempt is presumed dead. A completed response stays replayable for 24 hours. The key is scoped to the caller, not to the action: reusing it for a different action is answered with 409 or 422 rather than treated independently. On read actions this header is ignored. On write actions that cannot offer the guarantee it is answered with `400 IDEMPOTENCY_NOT_SUPPORTED` rather than silently ignored. |
| `id` | path | string | yes | The unique identifier of the vendor bill you want to reject. Example: `"3f1a8c25-9d47-4e60-b892-0c5a7e3b1d84"`. |

## Request body

Required, `application/json`: rejectVendorBillInput.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `reviewMessage` | string | no | Why the bill is being rejected, recorded against the approval decision. Omit for none. Example: `"Amount does not match the purchase order"`. |

```json
{
  "reviewMessage": "Amount does not match the purchase order"
}
```

## Response

`200` Success

Under `data` (rejectVendorBillOutput):

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `status` | string | yes | The bill status after the operation. The approval workflow decides it, so it is read back. |

```json
{
  "data": {
    "status": "<status>"
  },
  "diagnostics": [
    {
      "code": "<code>",
      "message": "<message>",
      "severity": "error",
      "path": [
        "<path>"
      ],
      "details": "<details>"
    }
  ]
}
```

## Response headers

- `Idempotency-Replayed` — Present and `true` only when this response replays a previously stored one for the same Idempotency-Key, rather than reflecting a live execution. Absent on a live response - never sent as `false`.

## Errors

| Code | Status |
| --- | --- |
| `NOT_FOUND` | 400 |
| `STATUS_CONFLICT` | 400 |
| `APPROVAL_FAILED` | 400 |
| `BILL_ALREADY_VOIDED` | 400 |
| `BILL_ALREADY_REVERSED` | 400 |
| `IDEMPOTENCY_KEY_CONFLICT` | 409 |
| `IDEMPOTENCY_PAYLOAD_MISMATCH` | 422 |

## Statuses

- `400` — Invalid request or business failure. Codes: NOT_FOUND, STATUS_CONFLICT, APPROVAL_FAILED, BILL_ALREADY_VOIDED, BILL_ALREADY_REVERSED
- `401` — The request carries no valid access token.
- `403` — Not authorized
- `404` — Not found
- `409` — The Idempotency-Key is still being processed by another request.
- `422` — The Idempotency-Key was already used with a different request payload.
- `429` — Too many requests from this client address. The response has no body and no `Retry-After` header.
- `500` — Internal server error