payroll reversal

I noticed that last month payroll for one week was processed 2 times by the new staff member, I only just picked it up because she is away and I was asked to do the payroll.  there are multiple entries in the electronic clearing account which I attempted to reverse thinking that this will clear the problem it did not. The amount that was sent to the ATO had zero amounts I had assumed that reversing the transaction will then clear the duplicate transaction.

Do I need to go and process the payroll again with negative amounts or is there an easier way.

How do I clear the amounts in the electronic clearing account