Hi Satish,
Go to sm37 job monitoring screen and double click on the job which you want to cancel.
In the menu click on Job Details tab.
New window will pop up. Collect WP number/PID from this screen.
Go to SM50 T-code. start Searching with WP number/PID. you will find one work processor for the same. Select that particular work process go to Process on top and select Cancel with core.
The job will be cancelled.
Lets say WP number/PID is 41/10354,758
search for WP 41 and check corresponding PID will be 10354758.
But be careful while selecting and cancelling the job.
Thanks