Hi Mothercarey,
When you are talking personal expenses in a business file then yes you should be allocating expenses and income via the "drawings" account mentioned by Kay.
But if you are talking about a legitimate business expense with a tax code you will need to use a journal entry. (company drop down menu)
If it was a bank transaction fee (for example), the reversing journal (to the additional transaction in the bank register) would be DR bank and CR the expense account you used previously, with the relevant tax code.
If you are reversing entries with GST/NCG/CAG in them I would recommend ticking the box in the bottom left hand corner which says amounts include tax.
If the duplicate transaction was in a current period however, you could just delete or void it.
The reason you cannot use the make/record deposit screen is because there is no option to assign a tax code which would make your BAS figures incorrect.
I hope this helps.
Kind regards,
Sally McIntosh (sally@samsolutions.com.au)