SSIS Connections cannot be changed

This a quite common issue you would come across, especially if you want to change the Data Source  of a SSIS Package and check some functionality against a different data source. Issue is, how many times you change it from Connection Manager (ex. Server Name), it jumps back to the previous value.

Reason behind this behavior is these details are associated with Parameters and sometimes it may be not present in the view.

You can right click the Project.params and view the code in such cases as shown below;

Now inspect the code;

You will realize that previous details (ex. Server) are set as shown above and they doesn't get change when you change the Connection Manager from UI. So you need to change this file with new details. This fix the issue.