Modify a User:
On the menu bar, click the Gear icon.
And on the left hand side menu, go to User Management.
Modify the parameters
A single click on the user you wish to modify will open up a screen where you can make the required changes. Once you are done, click Save.
Add or remove a Role
If you want to add or remove a role,: click on the arrow next to the list of roles and, in the next window, check additional roles or uncheck the roles you wish to remove. Once you are done, click Save.