Cancelling a job removes the job from your current jobs.  When you cancel a job, any relievers that have been assigned the job will be notified.  If you cancel a job before you have assigned a reliever, any relievers that have applied for the job will be notified.

Select ‘Calendar’
Click on the date of the job
A list of jobs published for this date will appear here. Select the job of you wish to cancel
Select ‘Cancel This Job'

Enter the reason for the cancellation here. The reliever will also be notified of this cancellation reason
Select ‘Yes – Cancel this Job’ to complete the cancellation. A notification will be sent to any assigned relievers informing them of the cancellation