Product:
Cognos BI 10.2.1 Cognos Connection

Problem:
User cannot replace a report in a folder with a different report he copied from a different folder. This is because the report to be pasted has different security settings for the user than the report in the target.
In the source folder you only have read, this means you can see reports and use them in report studio.
In the target folder you also have write access, this means you can create folders and paste reports there. But you cannot replace a report with a identical report from the source folder, because there the report is set with only READ access and not READ/WRITE.

Solution:
In the target folder you must have SET POLICY to be able to paste a report with other rights that the report you try to replace.
Workaround is to erase the report first, and then paste a new report into the folder. A new report does not change policy, and therefore can you save a report in a folder where you have write access.
If you only add new object to the target folder in Cognos Connection, you can manage with WRITE rights.
To work with a report or package you need to have READ, EXECUTE and TRAVERSE rights. If you only have EXECUTE and TRAVERSE you can run the report, or use the FM package in a report, but you cannot edit it in a Report Studio.