@MMB2023 

Agreed, you should not mess with the opening balance.  Reversing the entries from previous years is essentially deleting them but making them effective in the current year, which is what you want so as not to change previously closed periods.   As I'm sure you're aware, every entry on your Reconcile screen affects two accounts.  So, if these are bank transfers, each transfer affects two accounts, the one transferred from and the one transferred to, so make sure you want both accounts corrected.  You can reverse the entries with transfers (New > Transfer), checks, deposits, or journal entries - they all create debits and credits.  If these are bank transfers, creating transfers that reverse these entries is easiest.  Then, when you reconcile, clear the transfers against the duplicate transactions and all will be good.