Cancellation of a job is done via use of command ‘scancel’. The job under cancellation is invoked by its id.
scancel 123 (cancels job with jobid 123)
scancel 123 456 (cancels jobs with jobid’s 123 and 456)
scancel -u user1 (cancels all jobs of user user1)
scancel -t PD (cancels all pending jobs of user)