Which of the following cannot be done by a user to records owned by others when the organization wide default is set to Read / Write to an object?

CD.

When the organization-wide default is set to Read / Write to an object, it means that users can read, create, edit, and delete records that they own, as well as records that are owned by other users in the organization. However, there are certain actions that a user cannot perform on records owned by others, even when the organization-wide default is set to Read / Write. The answer to the question is option D - Change ownership.

Here is an explanation of each option:

A. Add related records: Users can add related records to a record they do not own, as long as they have the appropriate permissions to create the related record. For example, if a user has permission to create a new contact, they can create a new contact and link it to an account they do not own.

B. Search records: Users can search for records they do not own, as long as they have the appropriate permissions to view those records. The organization-wide default does not restrict users from searching for records they do not own.

C. Delete records: Users can delete records they do not own, as long as they have the appropriate permissions to delete those records. For example, if a user has permission to delete a case, they can delete a case owned by another user.

D. Change ownership: Users cannot change the ownership of a record they do not own, even if the organization-wide default is set to Read / Write. Only the owner of a record or a user with the "Transfer Record" permission can change the ownership of a record.

E. Report on records: Users can create reports on records they do not own, as long as they have the appropriate permissions to view those records. The organization-wide default does not restrict users from creating reports on records they do not own.

F. Edit details on records: Users can edit details on a record they do not own, as long as they have the appropriate permissions to edit that record. For example, if a user has permission to edit a lead, they can edit the details of a lead owned by another user.

In summary, when the organization-wide default is set to Read / Write to an object, users can perform most actions on records owned by others, except for changing ownership, which can only be done by the owner of the record or a user with the "Transfer Record" permission.