How change the installation standalone to network, after the product have installed in the version 2012??
You can't. In older releases this was possible. However the only way to make a stand-alone version into a network verison is to uninstall and reinstall properly.
Sorry.
Have a read of this thread
I have not tried it on 2012, but changing the registry as c3dlearner says did work on 2011.
I did not replace the PIT file as he points out as the machine I was converting was the only one with 2011 on it at the time.
Sorry to say that tried the method that used to work for 2011 and does not work for 2012.