Actually, the best place to do this is in the CMC.
1. Log in the CMC.
2. Locate the report.
3. Right-click on the report and select "Database Configuration".
4. Set the "Custom Database Logon" information.
5. Click on "Update".
6. Right-click on the report again and select "Refresh Options".
7. Uncheck "Default database logon information".
8. Click on "Update".
This will set the db login info for the new environment and steps 6-8 will, I think, set it so that the custom logon info will not be overwritten the next time that you update the report.
-Dell