$servername = "YOUR_SERVER";
$username = "YOUR_USERNAME";
$password = "YOUR_PASSWORD";
$dbname = "YOUR_DB";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$sql = "SELECT id, password FROM your_table";
$result = $conn->query($sql);

$newPasswords = [];

if ($result->num_rows > 0) {
    // output data of each row
    while($row = $result->fetch_assoc()) {
       $newPasswords[] = ["id" => $row["id"], "newPass" = "YOUR_PASSWORD_ENCRYPTED_WITH_BCRYPY"];
    }
} else {
    echo "0 results";
}

foreach($newPasswords as $user) {
$sql = "UPDATE your_table SET password = $user["newPass"] WHERE id = $user["id"]";
$result = $conn->query($sql);
}

$conn->close();