case 4:     // Requests current PIN, then asks for and sets new PIN
                System.out.print("**********************************************"
                        + "\nEnter current PIN: ");
                while (true) {
                    input = new Scanner(System.in);
                    String inputtedPin = input.next();

                    // Ensures PIN is 4 number characters
                    if (!inputtedPin.equals(accounts.get(inputtedId).getPin())) {
                        System.out.print("Invalid PIN. Please try again: ");
                        continue;
                    } else {
                        // Sets new PIN
                        System.out.print("\nEnter new 4-digit PIN: ");
                        inputtedPin = input.next();

                        // Ensures PIN is 4 number characters
                        while (!inputtedPin.matches("[0-9]{4}")) {
                            System.out.print("New PIN must be 4 digits. Please try again: ");
                            inputtedPin = input.next();
                        }
                    }

                    // Sets account PIN to the new one
                    accounts.get(inputtedId).setPin
                            (inputtedPin);
                    System.out.println("PIN successfully changed!");
                    mainMenu(accounts, inputtedId);
                    break;
                }
                break;