Bought a used Apple wireless keyboard (A1314) and want to restore to factory settings
I bought a used Apple wireless keyboard (A1314). I am attempting to pair it to my mac desktop but I already have an old Apple wireless keyboard (same model A1314) paired to it. I think I might be getting the bluetooth application confused but not sure. When I attempt to enter an access code from the newest (used) keyboard it is not recognizing that I'm entering the numbers and I keep getting a "failed to pair" message. This new (used) keyboard is named "System Administrator keyboard" by the previous owner. I would like to just restore it to factory settings and attempt all of this as if it were a new keyboard which has never been paired or named.
Any suggestions?
iMac 21.5", macOS 10.13