checksum when switching between source and dest addresses in IP header - newbie

Hello,

  I am not familiar with the details of checksum algorithm of ip headers;
My question is this:

When switching between source and dest addresses in an IP header of an
IP packet - should the checksum of the ip header be changed ?
Or is the checksum algorithm indifferent to which is the IP src address and
IP dest address in the ip header ?

Regards,
John