The easiest way to change the package server repository is to deploy the agent on the right Folder/Drive
in the acual agent Folder (C:\Program files\altiris\altiris agent) on the package server
run in cmd aexagentutil.exe /clean to desinstall the agent
copy aexnsc.exe on the package server
run aexnsc.exe -s NS=YourNSServer PATH="D:\WhereYouWantToInstallTheAgent" ADDREMOVE /s
after you promote the server as a package server in the console