You can rollback a posted Bank Reconciliation with the use of a series of SQL queries, if you are comfortable with using SQL Queries:
If you have copied your production company that includes the Bank Reconciliation you want to roll back to a Test Company, backup the Test Company. With a backup, you can go through the steps a number of times to make sure you are satisfied with the results.
When you are comfortable that the process will provide the results you want, backup your production company and perform the steps there. (Hopefully, only once)!
Query 1) Find the RECONUM of the reconciliation to be rolled back with the first query:
select * from CM20500
where CHEKBKID = 'ID of your Checkbook'
order by RECONUM
make a note of the LAST_RECONCILED__DATE & the LAST_RECONCILED_BALANCE.
These will be needed in the last steps.
2) Reset the RECOND flag, the Cleared Amount and the Cleared Date, and the RECONUM on the transactions included in that reconciliation:
set RECOND = 0
where RECONUM = 'The RECONUM identified by Query 1'
set CLRDAMT = 0
set CLEAREDATE = 0000-00-00
set RECONUM = 0
3) Remove the Reconciliation from history:
4) Update the Checkbook Master with the revised Last Recon Date and Last Recon Amount:
set LAST_RECONCILED _DATE = '2018-MM-DD 00:00:00.000′ (with whatever date is appropriate)
set LAST_RECONCILED_BALANCE = 'Beginning amount of the new Reconciliation'