Update Securities by Import ISIN

How can I import ISIN to update securities?

Trying:

  1. File, Import, CSV File, Select csv

  2. Type of Data: Securities, Ticker Symbol, ISIN

  3. Securities - The transactions below will be added if not crossed out
    (Brings up drop-down boxes of 14 Cash Accounts and 7 Security Accounts.)

I want to update all securities.

As far as I see, updating or enhancing doesn’t work. Only creation from scratch.
So this does work for watchlist stocks only, since others can’t be deleted.