What potential pitfalls should be considered when making changes to PHP code for a specific function?

When making changes to PHP code for a specific function, potential pitfalls to consider include introducing bugs or errors, breaking existing functionality, and impacting performance. It's important to thoroughly test the changes before deploying them to ensure they work as intended and do not cause any unintended consequences.

// Original function
function myFunction($param) {
    // Existing code
}

// Updated function with changes
function myFunction($param) {
    // New code
}