If you login as ADMIN and don't see Account Code Change, then you need to Activate it in Administrative Services

I assume you mean in Admin Services > Security Groups. Its not in the application drop-down menu. Where might it be hiding, or, more likely, was it not installed?  Can it be installed now?  Where would i find it?  Thanks!

Admin Services/Data Activation

When I open that I get a small pop-up window that simply says Sage 300 and has a green line that keeps running to the right. 

Beneath that is a second window that warns about backups and not proceeding without making a backup.  I have not checked proceed. 

What’s the green line mean?  What’s happening?

Check proceed, you don't need a backup

It worked!!!  Thank you very much for your help.