REST Api update fields

0

Hello,
I am trying to update some form fields and columns in an item list after some actions.
On my path i have configured a FOR EACH on my item list which is creating/composing JSON payload for my REST. (rows)
However, I am encountering an InternalServerError (500) when attempting to save this data using REST service on path for my current instance.

PATCH: api/data/v5.0/db/#{DBID}#/elements/#{WFD_ID}#


{
"workflow": {
"id": "#{WF:123}#"
},
"formType": {
"guid": "969c349e-ffba-4da3-ab12-1b800fc82a0f"
},
"formFields": [
{
"guid": "5e195656-8397-4997-8e18-2b890b71d867",
"svalue": "#{WFD_ID}#"
}
],
"itemLists": [
{
"guid": "e182eced-f3b7-4451-a278-255f6700f5c6",
"rows": #{RAW:2621}#, // JSON PAYLOAD
"formLayout": {
"editability": "Editable"
}
}
]
}

Is it possible to update item list using REST for current instance using a path (button) i press? for example: we have a simple process: START -> FINISH and on this path i have configured my actions and in the end REST action.

My situation is that, based on this item list, I am performing certain actions for each row, and I want to update some columns back.

Do you have any idea? thanks.