Cannot change password of private key

[skylarmt]

The following code is supposed to import and unlock a private key with a password, and then export the private key with a different password. However, the exported key uses the same password as the original key, and is in fact completely identical.

kbpgp.KeyManager.import_from_armored_pgp({
        armored: armoredkey
}, function (err, key) {
    if (!err) {
        if (key.is_pgp_locked()) {
            key.unlock_pgp({
                passphrase: "origpass"
            }, function (err) {
                if (!err) {
                    exportKey(key);
                } else {
                    console.error(err);
                }
            });
        } else {
            console.log("Loaded private key w/o passphrase");
             exportKey(key);
        }
    } else {
        console.error(err);
    }
});

function exportKey(key) {
    keymgr.export_pgp_private({
        passphrase: "newpass"
    }, function (err, pgp_private) {
        if (err) {
            console.error(err);
        } else {
            console.log(pgp_private);
            console.log("Private key backup saved.");
        }
    });
}