change control ideas for ERP application

I am after some generic advice around change management compliance testing for major ERP applications. From a risk perspective we want some assurance that major changes made to the production copy of our ERP application went through a managed change control process. We are trying to come up with a list of common “changes” to a production IT system that should go through formal change control. The obvious one is when applying new application patches or major releases on the production server. Are there any other common changes that you would recommend should go through change control?  Its a commercial software package and the code is not developed in house...