How do erase a code and add a new one? - Schlage BE365-CAM BE365CAM505 Lifetime Polished Brass Electronic Security K

The back plate of the keypad side of the lock on the exterior of the door has a sticker which includes the serial number, six digit programming code and two pre-programmed four digit user codes. The lock must be disassembled to a point the exterior of the lock can be pulled away from the door and the information on the sticker made note of.
This number is the programming code referenced in the information for changing the entry code.

This link will take you to the page that you need to get started:

http://consumer.schlage.com/Service-Support/Pages/InstructionandManuals.aspx

Then scroll down to this heading on that page:

Electronic Security-Keypad Deadbolt BE365

There's a wealth of info under that heading. You will be able to see a PDF file of the original print instructions, as well as a video of how to install the lock. This installation video (second item down) will be useful to allow you to disassemble it and view the sticker. This is also a great time to change the 9-volt battery! Batteries should be replace about every three years.
The seventh item under that same header is a video which walks you through how to reprogram the keypad to your new code, using that programming code that you found on the backside of the keypad.
A note about the PDF files: If you cannot view a given file, you need to first install Adobe reader. You can get the free download from here:

http://get.adobe.com/reader/

Good luck--and please provide feedback if this helps!