# Replaces the existing transaction units of a specific bookkeeping rule for the given client. 
The rule is identified by its unique rule ID. 
All current units will be removed and replaced with the units provided in the request body.

Endpoint: PUT /api/v1/clients/{clientId}/bookkeeping/transaction-rules/{ruleId}/field-mapping
Version: 1
Security: , , , 

## Path parameters:

  - `clientId` (string, required)

  - `ruleId` (string, required)

## Request fields (application/json):

  - `targetField` (string)
    Enum: "InvoiceNumber", "Description"

  - `value` (string)

## Response 200 fields (application/json):

  - `links` (object)

  - `clientId` (string)

  - `ruleId` (string)

## Response 403 fields (application/json):

  - `type` (string,null)

  - `title` (string,null)

  - `status` (integer,null)

  - `detail` (string,null)

  - `instance` (string,null)

## Response 404 fields (application/json):

  - `type` (string,null)

  - `title` (string,null)

  - `status` (integer,null)

  - `detail` (string,null)

  - `instance` (string,null)