edit component in *.intlib library
Within Altium you will need to go to File -> Open and open the .intlib file:



Altium will ask you what you want to do, to which you should answer "Extract Sources":



This will generate a SchLib and PcbLib file, located under a "LibPkg" project:



Once you've finished the edits to your library files you can either re-compile as an IntLib, or you can keep the SchLib and PcbLib files separate (which is what I prefer to do, personally).