Hi,
I think you can’t rename a package. you can rename only the folder or services/documents you create under a package
check whether that particular element is locked or not?
may be you are following a wrong naming convention which is not accepted by webMethods
if you are trying to rename a service,please check the dependencies for that particular service too.
Try shutting down the server and rename the folder inside of IntegrationServer/packages,
#webMethods#Integration-Server-and-ESB