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# updateCustomObject

Full update of a custom object instance (activity log records full diff).

Updates field values of an existing custom object instance identified by display ID
(e.g., "VEN-42") or internal numeric ID. Provide only the fields you want to change in `form_fields` —
unlisted fields are preserved.

## Parameters

| Name          | Type   | Required | Description                                                                   |
| ------------- | ------ | -------- | ----------------------------------------------------------------------------- |
| `id`          | string | Yes      | Display ID (e.g., "VEN-42", "VISA-100") or internal numeric ID (e.g., "157"). |
| `form_fields` | object | No       |                                                                               |