Many times I have needed to change network cards on a linux box, or I move a virtual machine and the nic mapping changes from
eth1. Thankfully it is really easy to fix if you just know where to look.
sudo vi /etc/udev/rules.d/70-persistent-net.rules
What you do is delete the top card from the list, and change the mapping on the bottom card to
:wq to save and exit and reboot. Congratulations! You have changed the network card mapping.