How to setup currency through API?

[emillod]

Hello
i want to create script which will update currency rate everyday. I have problem with API, because i find out how to GET actual currency rate, but i can't change this parameter.
I tried method PUT and POST. I tried to check API request from browser, when i edit through GUI - there is PUT method. But when i'm trying to send this request through API, i can't.

So:
1. i can GET currency
2. I can PUT currency
server answer with 403.

i used those parameters in request:
{
"currencyRates": {
"EUR": 4.2993,
"USD": 3.0000
}
}