I have just finalised my BAS, but realise that I need to change a transaction and redo the BAS.
If you have not lodged and paid your BAS amount to the ATO, you can delete the BAS you have just completed, making sure you also delete any actual payment transaction to the ATO in your Cashbook bank account (either automatically generated when you did your BAS, or added manually).
If you have already lodged and paid your BAS to the ATO, do not do the above. Instead, you may need to make an adjustment dated in the next period. Contact your accountant for advice on this mattter.