Create an instance of the DynamoDB client and invoke the updateTable method, providing the details of the new provisioned throughout capacity units. Here, we will update the read and write capacity units to two:

$tableName = 'productTablePHP';
$result = $client->updateTable(array(
    'TableName' => $tableName,
    'ProvisionedThroughput'    => array(
        'ReadCapacityUnits'    => 2,        
        'WriteCapacityUnits' => 2          
    )
));

DynamoDB takes some time to make the changes effective. So, it's a best practice to wait until the table gets effective again:

$client->waitUntilTableExists(array('TableName' => $tableName));