In addition to adding new roles, it is possible to modify existing roles. Doing so is handled in much the same way as adding new ones.
Just as with adding roles, modifying roles is handled within SQL Server Management Studio. You must have administrative rights to the reporting server to create new roles.
Open SQL Server Management Studio.
Connect to the instance of Reporting Services you wish to add new roles to.
Expand the Security branch.
Expand the Roles branch.
Right-click on the Report Builder predefined role.
Select Properties in the pop-up menu.
Place a check mark beside View data sources:
Figure 11.07
Click OK to save the changes.