You may need to cancel a Job before it's finished.
When you create a Job, you also create a contract between your organization and a contractor. If you cancel that Job, you cancel that contract at the same time. All of its associated Deliverables return to the "assignable" state (so they can be added to new Jobs), and the Job itself is marked inactive (so it won't appear in lists or searches).
(Note that if you have created a contract, but the contractor has not yet signed it, you can't cancel the Job, but need to revoke the contract instead.)
Go to the Jobs screen and click on the name of the Job you want to cancel.
Select the "Tools" tab.
Click the "Cancel Job" button. Because canceling a contract is irreversible, clicking the button bring up a confirmation pop-up window.
If you're sure you want to cancel the Job, click the "Proceed to Revoke Job" button on confirmation pop-up window.
Note: Canceling a Job can be a major decision, and may have financial or legal repercussions. For your organization's records, and the records of your contractor, you should make a comment on the Job detailing why the Job was canceled. (While canceled Jobs don't appear on the Jobs page by default, you can find them by including "inactive Jobs" in your search.)