if(isset($_POST['prinyato']) && !empty($_POST['id'])){
    $id =(int)($_POST['id']);
    if($id) {
        mysql_query('SELECT change_pr('.$id.')');
    } else {
        echo 'Id has not correct type';
    }
}

$result = mysql_query("
            SELECT
            holiday.id,
            holiday.Status AS Status
            FROM holiday
            INNER JOIN employee ON holiday.Personnel_Number = employee.Personnel_Number
            WHERE holiday.Status = 'Ожидает'",
    $db);

echo "<form action='redact_holiday.php' align='center' method='post'>";

while($myrow = mysql_fetch_array($result)){
    
    echo "<tr><th>".$myrow['id']."</th>";
    echo "<th>".$myrow['Status']."</th>";
    echo "<th><input type='submit' name='prinyato' value='Принято'/></th>";
    echo "<th><input type='submit' name='otkazano' value='Отказано'/></th>";
    echo '<input type="hidden" name="id" value="'.$_POST[$myrow['id']].'" /> ';
    echo "</tr>";
}
echo '</form>';

printf("Обновлено записей: %d\n", mysql_affected_rows());