Disarm your home security alarm. Go to the main menu and select the "User Settings" option. Make sure to read your alarm user manual carefully, since alarm systems and processes vary by manufacturer.
Enter the master code to access the information under the "User Setting" option. If you do not know the code, look in your user manual or call your security company.
Select the "Set User Codes" option. Push the "OK" or "Enter" button until you see your alarm code. Depending on the manufacturer, it may be labeled "User Code 1," "Security Code" or some other variation.
Enter your new alarm code using the keypad. Press "OK" or "Enter" to confirm the new code.
Press "Next" to access "User Code 2" or "Security Code 2," if necessary. Type in the second new code and press "Enter." Repeat until you have entered all your new codes.
Once you have reset all codes, arm your security system to make sure the new codes work.