Hi Gbad,

You can either recreate those transactions altogether, or make an adjusting journal entry to that BAS period if you want to change the totals showing. When preparing your BAS, QuickBooks Online takes into account all transactions entered into the file with the relevant tax codes associated to them in that date range. Therefore, if you would prefer not to recreate the transactions you removed, you could use a journal entry leaving and returning to the same account and enter a tax code on the journal - this would not affect that account's balance, but would be picked up by the GST centre when you come to prepare your BAS. This effectively 'edits' the totals so you can match them with what you have lodged with the ATO:

1. Select the + New button and select Journal entry. Enter a date that falls in the BAS period you are preparing. 
2. On Line 1, enter the account you'll be using for an adjustment (if you have a clearing or adjustment account already set up, you can use this, or create a new one. Speak with your accountant if you are unsure on the account type you should use). Enter the amount you need to make the adjustment by, then select the tax code you need to adjust for. Enter a description for the journal.
3. On Line 2, enter the same account used for Line 1. Enter the same amount to balance the journal, and enter the tax code Out of Scope. Enter a description, then select Save.

This journal creates an 'amendment' that will then reflect in the totals of the BAS you are marking as lodged. However before you proceed I would encourage you to reach out to your accountant or bookkeeper. While the journal entry method provided will 'amend' your totals and achieve the goal you are trying to attain, we are unable to advise what is best for your books as we are not accountants; they may have a preferred method of doing so or may encourage you to recreate the transactions instead. 

-Kass