my 2009 Impala has a transponder key, when adding new keys to the system what is being programed the new key,,,or the cars pcm

Cars, Changed, Chip, Computer, Just, Registered, Transponder, Values

If I buy a used transponder key from ebay that’s been used with another car can it be reprogrammed? Can the chip be replaced? If so, any ideas on how or where? Thanks.

Chip, Different, Operate, Replace, Reprogrammed, Transponder