You must have the appropriate privilege to delete a role. Perform the following:

1. Main navigation menu --> expand Users & Roles --> Manage Roles
2. On the next page, click on the Delete link corresponding to the role you want to delete (as shown in Figure 3.7a)
3. A confirmation dialog will open to receive your confirmation on this delete operation. 

Once you delete a role, all users having this role assigned to them will no longer have access to the resources assigned under this role.

Figure 3.7a: Screen showing a list of roles with delete buttons with each role.