can I change "the last reconciliation date" on the first screen when reconcile?

LTDan

I have made a mess of my account by changing my transactions form reconciled to cleared because one month the ending balance had changed after being reconciled. so to find the error, I tried to undo and then re-reconcile the reconcile the month. That was not working so I went back a month further.... and hence the mess.

NotACPA

Select all transactions from current going back until before "the mess".  Back to when the amount and date in Q match with a bank statement.

Change their CLR status to "c" (Cleared).

Then re-reconcile, month-by-month to correct the situation.  Once the error(s) are corrected, the remaining reconciliations (up to the present) should go pretty quickly.