Program to restart a particular step without other steps to get executed....

//--------JOB CARD----- RESTART=STEP3, COND=(0,EQ)
//STEP1 EXEC PGM=IEFBR14
//STEP2 EXEC PGM=SORT
//STEP3 EXEC PGM=IEBGENER
//STEP4 EXEC PGM=IEBCOPY






Here if you use above condition only the STEP3 will get executed all the other steps will get omitted...
or else you can use condition like  COND=(0,NE,ONLY)....