What to write here as a seconde option, when it's "NO" i dont want the app to do anything,this is C/AL, NAV

i have a problem ,What to write here as a seconde option, when it's "NO" i dont want the app to do anything ? this C/AL, NAV

 OnQueryClosePage(CloseAction : Action None) : Boolean
        IF CloseAction IN [ACTION::OK,ACTION::LookupOK] THEN BEGIN
           IF CONFIRM (STRSUBSTNO(CreateLedgerEnt,TRUE)) THEN
              LibraryLedgerMangement.CheckLedgerEntry(Book."No.");
              LibraryLedgerMangement.CreateLedgerEntry(Book."No.",LibraryCustomer."No.",1);

    ElSE ?