While changing data sources in current workbook it overwrites global permissions.

Hi, 

I'm to connected to the very same ODBC source in couple of my reports on the same credentials. Now I want to change them on one of my reports. ODBC source is going to be the same, but login and password to that database different. 

Now,  when I change login in data sources in current workbook all globall permissions are overwritten too and any other report files.

How do I change settings in current pbix file while not touching others?