Update GP worker additional information

Use this endpoint to correct or change country-specific additional information already held on a Global Payroll worker contract, for example after the worker reports a new marital status or a tax identifier changes. Only the fields sent under data are modified; everything else is left untouched. Field keys must belong to the additional-information fields defined for the contract country (see GET /rest/forms/gp/worker-additional-fields/{country_code}). For fields the organization has configured as effective-dated, a date must be supplied in effective_dates (YYYY-MM-DD) whenever the value changes: today or a past date applies the change immediately, a future date schedules it and the current value stays in effect until then. Unchanged values and clears need no date. Changes are recorded in the contract history and may update the worker onboarding checklist. By default returns 204. Pass ?include_completion_status=true to receive a 200 response with is_additional_data_done (true when all required fields for EDM onboarding are provided) and missing_keys (required fields still absent). Requires the people:write scope.

Token scopes: people:write