Hi Ashok,
As I Said earlier we do not have options to delete all automatically created reservation . We should delete the components and that will be automatically delete the reservation. SAP very clearly mentions in note 519580 - FAQ: Reservations that auto created reservations should be deleted at there source of reservation that is components should be deleted .In fact we do not have option to even go and manually change an auto created reservation in MB22. It kind of explains why we do not have standard mass program .
Either we need to go to individual Order and delete the components or develop custom LSMW or program which will do that . I searched again and I see no options to delete auto generated reservation in SAP using Mass program .
Note: Above stated comments are open for validation by experts .
Anjan