curl --request PATCH \
  --url https://api.treasuryprime.com/counterparty/{id} \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --data '{
  "userdata": {
    "ok": "true"
  }
}'

{
  "ach": {
    "account_number": "64141601",
    "account_type": "checking",
    "routing_number": "021001208"
  },
  "created_at": "2017-11-02T11:55:14Z",
  "id": "cp_1029384756",
  "name_on_account": "George Washington",
  "plaid_processor_token": null,
  "updated_at": "2017-11-02T11:55:14Z",
  "userdata": {
    "ok": "true"
  },
  "wire": null
}