REST API - Tasks

Get task list by API /bpm/api/4.0/tasks/ is easy (https://docs.oracle.com/en/cloud/saas/human-resources/20d/farws/Performing_Task_Action.html). My problem begins when I am trying to do action on task. When I am ask abut task I get possible action.

Copy
{
	...
    "actionList": [
	...
        {
            "actionId": "REASSIGN",
            "actionType": "System",
            "title": "REASSIGN",
            "length": 0
        },
        {
            "actionId": "APPROVE",
            "actionType": "Custom",
            "title": "Approve",
            "length": 0
        },
		...
    ]
	...
}

When I try to do this action I must have correct JSON file.

In document exist JOSON for APPROVE

{
    "action": {
        "id": "APPROVE"
    }
}

I have problem when I am trying to create longer JSON file for reassign action.

Information from link not help me. Maybe someone can help me in this subject.