Hi Sunil,
Where all that 1 entry has been reflected in your BW system. List out all the objects and then you can use selective deletion on all final data targets to zero out.
Delete the request from all targets and change the entry in PSA and then again loading from PSA to data targets is another option. Probably the best option.
Or can you make a same entry in BPC again, only this time in negative, and load it to BW, it automatically will zero out the BW entries.
Regards,
AR