You can delete the role from the existing roles list by following the below steps.
- Hover the Gear icon
- Select the Roles from the drop-down menu
- On hover over the at the right end of the user name, Click Delete icon
- Click Yes from the delete role modal
The role will be deleted permanently.
Roles cannot be deleted if it is assigned to any users. So it can only be deleted when the role is removed from the particular user or when it is not assigned to a user at the time of removal.