How to update Line Type Personalization in Requisition Form

Hi,

I have a situation in which I want to override the LOV for the line type field on the requisition form(POXRQERQ). The purpose is that I want to prevent the use of Service line type as at a specific date but for existing requisitions they can still be processed with the Service line type

Below is the forms personalization I have done without success;

1. Create condition

Trigger Event: WHEN-NEW-ITEM-INSTANCE

Trigger Object: LINES.LINE_TYPE

Condition: :LINES.QUANTITY is null and

:LINES.CREATION_DATE >to_date('26-OCT-2020' ,'DD-MON-YYYY') or

:LINES.CREATION_DATE is null

2. Action 1

Type: Builtin