What is needed from the BSI APP or WEB server if the IP or name of a remote Oracle database machine changes?
If the BSI database is moved to a new Oracle server with a new IP or name then you just need to change the Oracle tnsname entry that points to that database.
So from the APP and WEB server you could run Oracle's net configuration assistant (netca.exe) to change the server or just edit Oracle's tnsnames.ora file.
If the actual tnsname does not change but only the Oracle server, then there is no configuration change needed from the BSI side.
However if the tnsname changes as well then you would need to run BSI's passupdate.exe utility and specify the new name.