let login = <...>
let password = <...>
let saymonHostname = <...>
let userId = <...>
let path = "/node/api/users/" + userId;
let auth = "Basic " + btoa(login + ":" + password);
​
let headers = new Headers();
headers.append("Content-Type", "application/json");
headers.append("Authorization", auth);
​
let data = JSON.stringify({
    "permissions": [
        "manage-links"
    ]
});
​
let requestOptions = {
    method: "PATCH",
    headers: headers,
    body: data
};
​
fetch(saymonHostname + path, requestOptions)
    .then(response => response.text())
    .then(result => console.log(result))
    .catch(error => console.log("error", error));

const http = require("http");
​
let login = <...>
let password = <...>
let saymonHostname = <...>
let userId = <...>
let path = "/node/api/users/" + userId;
let auth = "Basic " + Buffer.from(login + ":" + password).toString("base64");
​
let options = {
    "method": "PATCH",
    "hostname": saymonHostname,
    "headers": {
        "Authorization": auth,
        "Content-Type": "application/json"
    },
    "path": path
};
​
let req = http.request(options, function (res) {
    let chunks = [];
​
    res.on("data", function (chunk) {
        chunks.push(chunk);
    });
​
    res.on("end", function (chunk) {
        let body = Buffer.concat(chunks);
        console.log(body.toString());
    });
​
    res.on("error", function (error) {
        console.error(error);
    });
});
​
let data = JSON.stringify({
    permissions: [
        "manage-links"
    ]
});
​
req.write(data);
req.end();

import requests
​
login = <...>
password = <...>
saymon_hostname = <...>
user_id = <...>
url = "https://" + saymon_hostname + "/node/api/users/" + user_id
​
body = {
    "permissions": [
        "manage-links"
    ]
}
​
response = requests.request("PATCH", url, json=body, auth=(login, password))
print(response.text)