I am currently recommending adding the following Automated Action:

if record.move_name and not record.journal_entry_ids:  
    record['move_name'] = False

It will reset the Bank Statement Line (make it forget it was reconciled with something else) so you can re-reconcile with the correct payment/account.

keywords:

re-reconcile bank statement line unreconcile bank statement line reset bank statement line bank statement mistake bank statement line mistake bank statement line reconciled with incorrect account bank statement line reconciled with incorrect payment.

When a bank statement line is reconciled with a payment (or reconciled directly to an account using a reconcilation model) the resulting Journal Entry is stored in the move_name field. 

If reverting bank statement line reconcilations is allowed (account_cancel is installed and the bank journal is setup to allow cancelling entries) then the bank statement line keeps a value in move_name after the revert has been made.

This prevents the line from being reconciled with the correct entry. 

The Automated Action I refer to resets the contents of the move_name field to False after the revert has been made (since the Journal Entry no longer exists) so that the line can be reconciled with something else. 

This makes it SO EASY to re-reconcile a bank statement line after it has been incorrectly reconciled with the wrong payment (or reconciled directly to an account). 

RESET TO NEW the Bank Statement, REVERT the line that was incorrectly reconciled, click RECONCILE, find and reconcile with the correct entry, close the Bank Statement. 

Since the Journal Entry is deleted once the REVERT button is clicked, I couldn't think of a reason to keep it in the move_name field, and I can't see a reason not to allow re-reconcilation in this way if you are allowed to cancel and delete journal entries - so I am recommending this process as an easy way to resolve mistakes made during bank rec - without having to reverse journal entries and re-create bank statement lines (which is the only way I can see how to do it without this Automated Action).