Letter Of Ä°ndemnity and Bill of Lading

[edilee]

hello
in seldom cases
there is some petrol letter of credits that requires letter of indemnity instead of bill of lading.

İn these letter of indemnities the sellers undertake the presentation of the B/L
how is it work.What happens after the pesentation of LOI and what is the responsibility of the bank in that cases.

finally is the B/L must be presented to the bank.
is there any one experience may share with us
thanks in advance