Hi rishiraj,
First u have to go to t-code vl02n ,then enter ur delivery num and open it ,and press delete option, if it I'll display item xx cannot be deleted, then go to t-code vl09 ,reverse the goods , then again u can go to vl02n and open ur delivery doc ,now click on delete option then u get the solution..
Thanks,
Regards
Suman.