curl --request POST \
  --url https://{server}/api/assets/permissions/bulk-merge/ \
  --header 'Content-Type: application/json' \
  --cookie sessionid= \
  --data '
{
  "asset_ids": [
    "3c90c3cc-0d44-4b50-8888-8dd25736052a"
  ],
  "upsert": [
    {
      "flags": 2,
      "subject_type": "user",
      "subject_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
    }
  ],
  "remove_subjects": [
    {
      "subject_type": "user",
      "subject_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
    }
  ],
  "remove_user_ids": [
    {
      "subject_type": "user",
      "subject_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
    }
  ]
}
'