How can you ensure that the replace and lowercase functions only affect specific instances of a variable within a PHP script?

To ensure that the replace and lowercase functions only affect specific instances of a variable within a PHP script, you can create a new variable to store the modified value while keeping the original variable intact. This way, you can manipulate the new variable without altering the original one.

$originalVariable = "Hello World";
$modifiedVariable = strtolower(str_replace("Hello", "Hi", $originalVariable));

echo $originalVariable; // Output: Hello World
echo $modifiedVariable; // Output: Hi World