PUT to update the specified order...
/api/v3/orders/:id
For example...
{
"order": {
"custom_order_id": "O123",
"email": "joe@example.com",
"first_name": "John",
"last_name": "Doe"
}
}
NOTE: price is optional and defaults to the price set in the UI if not present.send_email is optional and defaults to false if not present. All fields can be changed including the order ID.