Change header

["Daniel Mon" <cdanielmon@xxxxxxxxxxx>]

Hello, my name is Daniel and need your help. I need change the header IP of 
192.168.0.* to 10.0.12.* and save the finish  number of IP, is it possible? 
Thanks for your help. Sorry for my english is very bad, Bye.



                       Mon Carlos Daniel
              web: http://www.carlosmon.com.ar