User Impersonation - ‘x-impersonate-uuid' usage

I would like to know more about how to use User Impersonation

I need to mark jobs as completed by a specific staff member.
The following does not appear to work

curl -X POST "https://api.servicem8.com/api_1.0/job/JOB_UUID_HERE.json" ^
  -H "X-Api-Key: API-KEY-HERE" ^
  -H "x-impersonate-uuid: STAFF_UUID_HERE" ^
  -H "accept: application/json" ^
  -H "content-type: application/json" ^
  -d "{ \"completion_date\": \"2025-09-12 12:00:00\", \"status\": \"Completed\" }"

Please provide a working curl example of an API POST to job/{uuid}.json to complete a job as a specific staff

Cheers