>I have a very large script. In order to have it compiled, I need to place a GO where I create some fields so the code below would be able to compile. However, now that I have that, it means the @Command variable down below does not inherit from the previous declaration as it seems the GO command wipes out the memory of the declarations. Is there a way to have a GO command and not loosing the declarations?

No. GO marks the end of a batch. GO is not a part of T-SQL but end of batch marker for a tool that executes the script