The problem is that an isin does not identify the exchange, only an issuer.
Let's say your isin is US4592001014
(IBM), one way to do it would be:
get the ticker (in A1):
=BDP("US4592001014 ISIN", "TICKER") => IBM
get a proper symbol (in A2)
=BDP("US4592001014 ISIN", "PARSEKYABLE_DES") => IBM XX Equity
where
XX
depends on your terminal settings, which you can check onCNDF <Go>
.get the main exchange composite ticker, or whatever suits your need (in A3):
=BDP(A2,"EQY_PRIM_SECURITY_COMP_EXCH") => US
and finally:
=BDP(A1&" "&A3&" Equity", "LAST_PRICE") => the last price of IBM US Equity