Right of pre‑emption is a right of prior purchase, in Bengali it is called অগ্রক্রয়  and by pre‑emption the pre‑emptor purchases the property at the price at which it is transferred with statutory costs. 

( Hafiz Ahmed Vs. Ahmedur Rahman and others, 1995, 24 CLC (HCD) [7480] )

Pre- emption is the right to purchase something in advance of others or a prior appropriation of something. 

If a pre-emptor succeeds in having the property transferred to himself from the purchaser by private arrangements instead of bringing a suit, it would not be right to say that he has not exercised his right of pre-emption. 

( Mehr Baksh vs. Mala Dad, 3 DLR (1951) 224 )