I forget my backup pin and phone is not allowing me to access it. How do I reset the pin?
The only way to reset the PIN is through Recovery Mode using Wipe or Flashing a script. remove the S-Pen, then press Volume Up + Home _+ Power button until you enter Recovery. In recovery, either use Wipe Data which will restore the device to factory condition, or flash the script from the XDA Developers. Put the file on the SD card and then use the Install Update option in Recovery.
Script location: http://forum.xda-developers.com/note-4/orig-development/bypass-lock-screen-pattern-password-pin-t2948336