https://www.netsuiterp.com/2019/04/update-custom-form-of-existing-leads.html
NetSuite Development Notes: Update the Custom Form of Existing Leads, Prospects, or Customers...
To change the form of existing Prospects, Leads or Customers, perform the steps below: Note: User must prepare a CSV file with the Internal...
prospects or customersdevelopment notesnetsuiteupdateform