I am struggling with the same issue of trying to save an account as a sub account. I disconnected the account from I  wanted to identify as a sub account from online banking & then reactivated it.  When it was reconnected to online banking, I tried to set it up as a sub account and got the message,  "You can't change the parent of this account to "XXX" (Parent Acct for reconciliation) because it or its parent account is already set up for Online Banking or Web Connect.  Do I have to disconnect the parent account also?  What will I lose?