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

# Update exemption certificate

> Update an existing exemption certificate

Updates specific fields of an exemption certificate. At least one field must be provided for update.

<ParamField path="exemption_certificate_id" type="string" required>
  The unique identifier of the exemption certificate to update.
</ParamField>

<ParamField body="effective_date" type="string">
  The effective date of the exemption certificate in ISO 8601 format (YYYY-MM-DD).
</ParamField>

<ParamField body="exemption_certificate_number" type="string">
  The exemption certificate number. Maximum 20 characters.
</ParamField>

<ParamField body="file_id" type="string">
  The ID of the file associated with this exemption certificate.
</ParamField>

<ResponseExample>
  ```json 200 theme={null}
  {
    "message": "Successfully updated exemption certificate."
  }
  ```

  ```json 400 theme={null}
  {
    "error": {
      "code": "INVALID_REQUEST_BODY",
      "message": "At least one field must be provided for update"
    }
  }
  ```

  ```json 404 theme={null}
  {
    "error": {
      "code": "EXEMPTION_CERTIFICATE_NOT_FOUND",
      "message": "Exemption certificate not found"
    }
  }
  ```
</ResponseExample>

<RequestExample>
  ```bash cURL theme={null}
  curl --request POST \
    --url 'https://transaction-tax.api.in.commenda.io/api/v1/exemption-certificates/{exemption_certificate_id}' \
    --header 'Authorization: Bearer <token>' \
    --header 'Content-Type: application/json' \
    --data '{
      "effective_date": "2024-01-01",
      "exemption_certificate_number": "EX-12345"
    }'
  ```

  ```javascript JavaScript theme={null}
  const response = await fetch('https://transaction-tax.api.in.commenda.io/api/v1/exemption-certificates/{exemption_certificate_id}', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer <token>',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      effective_date: '2024-01-01',
      exemption_certificate_number: 'EX-12345'
    })
  });

  const data = await response.json();
  ```

  ```python Python theme={null}
  import requests

  response = requests.post(
    'https://transaction-tax.api.in.commenda.io/api/v1/exemption-certificates/{exemption_certificate_id}',
    headers={'Authorization': 'Bearer <token>'},
    json={
      'effective_date': '2024-01-01',
      'exemption_certificate_number': 'EX-12345'
    }
  )

  data = response.json()
  ```
</RequestExample>