upgrading external eeprom

I've got a PIC program that someone else wrote that records some data and stores it to a 24LC256A (256K) eeprom. I'm not good with editing the raw code yet. How much trouble would it be to change the code so that I could upgrade the external eeprom to a 24LC512 so I could have twice the data storage capacity?

I suppose this would be easy.
The capacity of memory should be defined in somewhere in your code. If there is, just change its value.