If you don't get the global database name right during an Oracle installation, i.e., if you just specified the sid for global database name, what could possibly go wrong? Must you uninstall and specify or is there a shortcut to this?
As long as you are not using Real Application Clusters, Advanced Replication or Streams Replication, the global name should rarely come into play. So I wouldn't worry about it. If you do have to change the global name, you can specify a new one with the following command:
ALTER SYSTEM SET global_name=new_value SCOPE=spfile;
Then bounce your instance.