HWH-UBL=> BP changed to BZA.
Berth got split into atleast two with one HWH-BZA passenger getting confirmation and then the same berth getting forwarded to this passenger.
Simple concept of berth forwarding.
Same would happen in HWH-MAS Mail if you book from HWH to MAS with boarding point at VSKP or if you book by Howrah Rajdhani from HWH to NDLS with boarding point...
more... at CNB.
Easy confirmation (Obviously upto a certain limit)