При нажатии кнопки Like/Dislike увеличить счётчик, а при повторном нажатии - вернуть в исходное состояние

Есть рабочий пример оценки комментариев. Все работает (нажимаешь Like- плюс 1, нажимаешь Dislike - минус 1). Только как вернуть все в исходное состояние при повторном нажатии кнопки?

<?
// Checking the id of the evaluated comment received via javascript
if (isset($_POST["comm_id"]) and is_numeric($_POST["comm_id"]))
    $obj = $_POST["comm_id"];
else $obj = '';

// Checking the "rate" sent via JS with a value of 1
if (isset($_POST["rate"]) and ($_POST["rate"] == 0 or $_POST["rate"] == 1))
    $rate = $_POST["rate"];
else $rate = '';

if ($rate != '' and $obj > 0) {
    $rating_plus = 0;
    $rating_minus = 0;

    if ($rating_plus == 0 and $rating_minus == 0) {
        if ($rate == 0) $rating_minus++;
        else $rating_plus++;
    }
    
    else {
        if ($rate == 0) {
            $rating_minus++;
            $rating_plus--;
        } else {
            $rating_minus--;
            $rating_plus++;
        }
        
    }

    //Calculating the rating of a comment

    $sum = $rating_plus - $rating_minus;        
   
    if ($sum < 0) $color_sum = '#865656';
    else {
        $color_sum = '#688656';
        if ($sum == 0) $color_sum = '#888';
    }
    
    $rating_sum = '<b style="color: '.$color_sum.'">'.$sum.'</b>';
    
   // Forming a response
    $output = ['rating_sum' => $rating_sum];
    exit(json_encode($output));
}



//Calculating the rating of a comment
$sum = $Row["plus"] - $Row["minus"];
if ($sum < 0) $comm_rate = '<b style="color: #865656">'.$sum.'</b>';
    else {
        $comm_rate = '<b style="color: #688656">'.$sum.'</b>';
        if ($sum == 0) $comm_rate = '<b style="color: #888">'.$sum.'</b>';
    }
// --/-- //  

$Row["id"] = 4;        
        
$com_rating = '
<div class="rating_com">
    <div class="comm_plus">Like</div>
    <div class="comm_rate" id="rating_comm'.$Row["id"].'">
        '.$comm_rate.'
    </div>
    <div class="comm_minus">Dislike</div>
</div>';


echo '
    <div class="comments" id="m'.$Row["id"].'">
        <div class="com_block">         
            <div class="name">$Name</div>
            <div class="companel">
                '.$com_rating.'
            </div>
            <p>$Row["text"]</p>
    </div>';

?>


<script>
    
document.querySelectorAll('.comm_plus,.comm_minus,.comm_rate').forEach(arm =>{
    arm.addEventListener('click', e => {
        var id_comm = e.target.closest(".comments").getAttribute('id').substr(1); // we get the id of the rated comment and trim the first letter.
        // Check if "comm_plus" was pressed, then the value "1" will be sent to $_POST['rate']
        if (arm.classList.contains("comm_plus")) var num = 1;
        if (arm.classList.contains("comm_minus")) var num = 0;
    
        var xmlhttp = getXmlHttp(); 
        xmlhttp.open('POST', '/news/material', true); 
        xmlhttp.responseType = 'json';
        xmlhttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        xmlhttp.send(`rate=${num}&comm_id=` + encodeURIComponent(id_comm)); 
        xmlhttp.onreadystatechange = function() { 
            if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { 
                const response = xmlhttp.response;               
                var com_rate = document.getElementById(`rating_comm`+id_comm);
                com_rate.classList.add('_active');
    
                setTimeout(() => { 
                    com_rate.classList.remove('_active');
                    com_rate.innerHTML = `${response.rating_sum}`; 
                }, 500);
            }
        };
            
    });
});

// The function creates an XMLHTTP object to send data to a POST request (without using an html form) 
function getXmlHttp() {
    var xmlhttp;
    try {
        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
        try {
            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        } catch (E) {
            xmlhttp = false;
        }
    }
    if (!xmlhttp && typeof XMLHttpRequest!='undefined') xmlhttp = new XMLHttpRequest();
    return xmlhttp;
}

</script>



<style>
.comments {width: 60%; margin: 4em 2em; border: 2px solid grey; border-radius: 10px; padding: 1em}
.com_block .name {display: inline-block; margin: 0 0 7px;}
.com_block .companel {float: right; color: #6A6E68;}
.comment_edit {padding: 6px}
.comment_edit #button {margin-top: 4px}
.rating_com {margin: 0 5px 0 9px}
.rating_com div {display: inline-block}
.comm_minus, .comm_plus {cursor: pointer}
</style>