Only owner(one who created the workspace) only holds the right to delete the workspace.
You are Owner:
`````````````````````
You are not Owner
``````````````````````````
If you are not owner of workspace than you can only leave the workspace by clicking on MANAGE WORKSPACE button at the bottom left corner of the page.
Select the MANAGE TEAM options from the menu and from the user list remove yourself or any other user you want to remove.